Compound nouns 
Most English compound nouns are noun phrases (= nominal phrases) that include a noun modified by adjectives or attributive nouns. Due to the English tendency towards conversion, the two classes are not always easily distinguished. Most English compound nouns that consist of more than two words can be constructed recursively by combining two words at a time. Combining "science" and "fiction", and then combining the resulting compound with "writer", for example, can construct the compound "science fiction writer". Some compounds, such as salt and pepper or mother-of-pearl, cannot be constructed in this way, however.
Types of compound nouns 
Since English is a mostly analytic language, unlike most other Germanic languages, it creates compounds by concatenating words without case markers. As in other Germanic languages, the compounds may be arbitrarily long. However, this is obscured by the fact that the written representation of long compounds always contains blanks. Short compounds may be written in three different ways, which do not correspond to different pronunciations, however:
- The "solid" or "closed" forms in which two usually moderately short words appear together as one. Solid compounds most likely consist of short (monosyllabic) units that often have been established in the language for a long time. Examples are housewife, lawsuit, wallpaper, basketball, etc.
- The hyphenated form in which two or more words are connected by a hyphen. Compounds that contain affixes, such as house-build(er) and single-mind(ed)(ness), as well as adjective-adjective compounds and verb-verb compounds, such as blue-green and freeze-dried, are often hyphenated. Compounds that contain articles, prepositions or conjunctions, such as rent-a-cop, mother-of-pearl and salt-and-pepper, are also often hyphenated.
- The open or spaced form consisting of newer combinations of usually longer words, such as distance learning, player piano, lawn tennis, etc.
Usage in the US and in the UK differs and often depends on the individual choice of the writer rather than on a hard-and-fast rule; therefore, open, hyphenated, and closed forms may be encountered for the same compound noun, such as the triplets container ship/container-ship/containership and particle board/particle-board/particleboard.
In addition to this native English compounding, there is the classical type, which consists of words derived from Latin, as horticulture, and those of Greek origin, such as photography, the components of which are in bound form (connected by connecting vowels, which are most often -i- and -o- in Latin and Greek respectively) and cannot stand alone.
Analyzability (transparency) 
In general, the meaning of a compound noun is a specialization of the meaning of its head. The modifier limits the meaning of the head. This is most obvious in descriptive compounds (known as karmadharaya compounds in the Sanskrit tradition), in which the modifier is used in an attributive or appositional manner. A blackboard is a particular kind of board, which is (generally) black, for instance.
In determinative compounds, however, the relationship is not attributive. For example, a footstool is not a particular type of stool that is like a foot. Rather, it is a stool for one's foot or feet. (It can be used for sitting on, but that is not its primary purpose.) In a similar manner, an office manager is the manager of an office, an armchair is a chair with arms, and a raincoat is a coat against the rain. These relationships, which are expressed by prepositions in English, would be expressed by grammatical case in other languages. (Compounds of this type are known as tatpurusha in the Sanskrit tradition.)
Both of the above types of compounds are called endocentric compounds because the semantic head is contained within the compound itself—a blackboard is a type of board, for example, and a footstool is a type of stool.
However, in another common type of compound, the exocentric or (known as a bahuvrihi compound in the Sanskrit tradition), the semantic head is not explicitly expressed. A redhead, for example, is not a kind of head, but is a person with red hair. Similarly, a blockhead is also not a head, but a person with a head that is as hard and unreceptive as a block (i.e. stupid). And, outside of veterinary surgery, a lionheart is not a type of heart, but a person with a heart like a lion (in its bravery, courage, fearlessness, etc.).
Note in general the way to tell the two apart:
- Can you paraphrase the meaning of the compound "[X . Y]" to A person/thing that is a Y, or ... that does Y, if Y is a verb (with X having some unspecified connection)? This is an endocentric compound.
- Can you paraphrase the meaning if the compound "[X . Y]" to A person/thing that is with Y, with X having some unspecified connection? This is an exocentric compound.
Exocentric compounds occur more often in adjectives than nouns. A V-8 car is a car with a V-8 engine rather than a car that is a V-8, and a twenty-five-dollar car is a car with a worth of $25, not a car that is $25. The compounds shown here are bare, but more commonly, a suffixal morpheme is added, esp. -ed. Hence, a two-legged person is a person with two legs, and this is exocentric.
On the other hand, endocentric adjectives are also frequently formed, using the suffixal morphemes -ing or -er/or. A people-carrier is a clear endocentric determinative compound: it is a thing that is a carrier of people. The related adjective, car-carrying, is also endocentric: it refers to an object, which is a carrying-thing (or equivalent, which does carry).
These types account for most compound nouns, but there are other, rarer types as well. Coordinative, copulative or dvandva compounds combine elements with a similar meaning, and the compound meaning may be a generalization instead of a specialization. Bosnia-Herzegovina, for example, is the combined area of Bosnia and Herzegovina, but a fighter-bomber is an aircraft that is both a fighter and a bomber. Iterative or amredita compounds repeat a single element, to express repetition or as an emphasis. Day by day and go-go are examples of this type of compound, which has more than one head.
Analyzability may be further limited by cranberry morphemes and semantic changes. For instance, the word butterfly, commonly thought to be a metathesis for flutter by, which the bugs do, is actually based on an old bubbe meise that butterflies are petite witches that steal butter from window sills. Cranberry is a part translation from Low German, which is why we cannot recognize the element cran (from the Low German kraan or kroon, "crane"). The ladybird or ladybug was named after the Christian expression "our Lady, the Virgin Mary".
In the case of verb+noun compounds, the noun may be either the subject or the object of the verb. In playboy, for example, the noun is the subject of the verb (the boy plays), whereas it is the object in callgirl (someone calls the girl).
Sound patterns 
Stress patterns may distinguish a compound word from a noun phrase consisting of the same component words. For example, a black board, adjective plus noun, is any board that is black, and has equal stress on both elements. The compound blackboard, on the other hand, though it may have started out historically as black board, now is stressed on only the first element, black. Thus a compound such as the White House normally has a falling intonation which a phrase such as a white house does not.
Compound modifiers 
A compound modifier is a sequence of modifiers of a noun that function as a single unit. It consists of two or more words (adjectives, gerunds, or nouns) of which the left-hand component modifies the right-hand one, as in "the dark-green dress": dark modifies the green that modifies dress.
Solid compound modifiers 
There are some well-established permanent compound modifiers that have become solid over a longer period, especially in American usage: earsplitting, eyecatching, and downtown.
However, in British usage, these, apart from downtown, are more likely written with a hyphen: ear-splitting, eye-catching.
Other solid compound modifiers are for example:
- Numbers that are spelled out and have the suffix -fold added: "fifteenfold", "sixfold".
- Points of the compass: northwest, northwestern, northwesterly, northwestwards. In British usage, the hyphenated and open versions are more common: north-western, north-westerly, north west, north-westwards.
Hyphenated compound modifiers 
Major style guides advise consulting a dictionary to determine whether a compound modifier should be hyphenated; the dictionary's hyphenation should be followed even when the compound modifier precedes a noun. Hyphens are unnecessary in other unambiguous, regularly used compound modifiers.
Generally, a compound modifier is hyphenated if the hyphen helps the reader differentiate a compound modifier from two adjacent modifiers that modify the noun independently. Compare the following examples:
- "small appliance industry": a small industry producing appliances
- "small-appliance industry": an industry producing small appliances
The hyphen is unneeded when capitalization or italicization makes grouping clear:
- "old English scholar": an old person who is English and a scholar, or an old scholar who studies English
- "Old English scholar": a scholar of Old English.
- "De facto proceedings" (not "de-facto")
If, however, there is no risk of ambiguities, it may be written without a hyphen: Sunday morning walk.
Hyphenated compound modifiers may have been formed originally by an adjective preceding a noun, when this phrase in turn precedes another noun:
- "Round table" → "round-table discussion"
- "Blue sky" → "blue-sky law"
- "Red light" → "red-light district"
- "Four wheels" → "four-wheel drive" (historically, the singular or root is used, not the plural)
Others may have originated with a verb preceding an adjective or adverb:
- "Feel good" → "feel-good factor"
- "Buy now, pay later" → "buy-now pay-later purchase"
Yet others are created with an original verb preceding a preposition.
- "Stick on" → "stick-on label"
- "Walk on" → "walk-on part"
- "Stand by" → "stand-by fare"
- "Roll on, roll off" → "roll-on roll-off ferry"
The following compound modifiers are always hyphenated when they are not written as one word:
- An adjective preceding a noun to which -d or -ed has been added as a past-participle construction, used before a noun:
- A noun, adjective, or adverb preceding a present participle:
- "an awe-inspiring personality"
- "a long-lasting affair"
- "a far-reaching decision"
- Numbers, whether or not spelled:
- A numeral with the affix -fold has a hyphen (15-fold), but when spelled out takes a solid construction (fifteenfold).
- Numbers, spelled out or not, with added -odd: sixteen-odd, 70-odd.
- Compound modifiers with high- or low-: "high-level discussion", "low-price markup".
- Colours in compounds:
- "a dark-blue sweater"
- "a reddish-orange dress".
- Fractions as modifiers are hyphenated: "five-eighths inches", but if numerator or denominator are already hyphenated, the fraction itself does not take a hyphen: "a thirty-three thousandth part". (Fractions used as nouns have no hyphens: "I ate only one third of the pie.")
- Comparatives and superlatives in compound adjectives also take hyphens:
- "the highest-placed competitor"
- "a shorter-term loan"
- However, a construction with most is not hyphenated:
- "the most respected member".
- Compounds including two geographical modifiers:
- But not
The following compound modifiers are not normally hyphenated:
- Compound modifiers that are not hyphenated in the relevant dictionary or that are unambiguous without a hyphen.
- Where there is no risk of ambiguity:
- "a Sunday morning walk"
- Left-hand components of a compound modifier that end in -ly and that modify right-hand components that are past participles (ending in -ed):
- "a hotly disputed subject"
- "a greatly improved scheme"
- "a distantly related celebrity"
- Compound modifiers that include comparatives and superlatives with more, most, less or least:
- "a more recent development"
- "the most respected member"
- "a less opportune moment"
- "the least expected event"
- Ordinarily hyphenated compounds with intensive adverbs in front of adjectives:
- "very much admired classicist"
- "really well accepted proposal"
Using a group of compound nouns containing the same "Head" 
Special rules apply when multiple compound nouns with the same "Head" are used together, often with a conjunction (and with hyphens and commas if they are needed).
- The third- and fourth-grade teachers met with the parents.
- Both full- and part-time employees will get raises this year.
- We don't see many 3-, 4-, and 5-year-old children around here.
Compound verbs 
|preposition||verb||overrate, underline, outrun|
|adjective||verb||whitewash, blacklist, foulmouth|
|noun||verb||browbeat, sidestep, manhandle|
A compound verb is usually composed of a preposition and a verb, although other combinations also exist. The term compound verb was first used in publication in Grattan and Gurrey's Our Living Language (1925).
From a morphological point of view, some compound verbs are difficult to analyze because several derivations are plausible. Blacklist, for instance, might be analyzed as an adjective+verb compound, or as an adjective+noun compound that becomes a verb through zero derivation. Most compound verbs originally have the collective meaning of both components, but some of them later gain additional meanings that may supersede the original, emergent sense. Therefore, sometimes the resultant meanings are seemingly barely related to the original contributors.
Compound verbs composed of a noun and verb are comparatively rare, and the noun is generally not the direct object of the verb. In English, compounds such as *bread-bake or *car-drive do not exist. Yet, we find literal action words, such as breastfeed, and washing instructions on clothing as for example hand wash.
Compound verbs with single-syllable modifiers are solid, or unhyphenated. Those with longer modifiers may originally be hyphenated, but as they became established, they became solid, e.g.,
- overhang (English origin)
- counterattack (Latin origin)
There was a tendency in the 18th century to use hyphens excessively, that is, to hyphenate all previously established solid compound verbs. American English, however, has diminished the use of hyphens, while British English is more conservative.
Phrasal verbs 
- I held up my hand.
- I held up a bank.
- I held my hand up.
- *I held a bank up.
The first three sentences are possible in English; the last one is unlikely. When to hold up means to raise, it is a prepositional verb; the preposition up can be detached from the verb and has its own individual meaning "from lower to a higher position". As a prepositional verb, it has a literal meaning. However, when to hold up means to rob, it is a phrasal verb. A phrasal verb is used in an idiomatic, figurative or even metaphorical context. The preposition is inextricably linked to the verb; the meaning of each word cannot be determined independently but is in fact part of the idiom.
The Oxford English Grammar (ISBN 0-19-861250-8) distinguishes seven types of prepositional or phrasal verbs in English:
- intransitive phrasal verbs (e.g. give in)
- transitive phrasal verbs (e.g. find out [discover])
- monotransitive prepositional verbs (e.g. look after [care for])
- doubly transitive prepositional verbs (e.g. blame [something] on [someone])
- copular prepositional verbs. (e.g. serve as)
- monotransitive phrasal-prepositional verbs (e.g. look up to [respect])
- doubly transitive phrasal-prepositional verbs (e.g. put [something] down to [someone] [attribute to])
English has a number of other kinds of compound verb idioms. There are compound verbs with two verbs (e.g. make do). These too can take idiomatic prepositions (e.g. get rid of). There are also idiomatic combinations of verb and adjective (e.g. come true, run amok) and verb and adverb (make sure), verb and fixed noun (e.g. go ape); and these, too, may have fixed idiomatic prepositions (e.g. take place on).
Misuses of the term 
"Compound verb" is often used in place of:
- "complex verb", a type of complex phrase. But this usage is not accepted in linguistics, because "compound" and "complex" are not synonymous.
- "verb phrase" or "verbal phrase". This is a partially, but not entirely, incorrect use. A phrasal verb can be a one-word verb, of which compound verb is a type. However, many phrasal verbs are multi-word.
- "phrasal verb". A sub-type of verb phrase, which have a particle as a word before or after the verb.
See also 
- When said in isolation, additional prosodic stress falls on the second word, but this disappears in the appropriate context.
- Some dictionaries mark secondary stress on the second element, board. However, this is a typographic convention due to the lack of sufficient symbols to distinguish full from reduced vowels in unstressed syllables. See secondary stress for more.
- A similar falling intonation occurs in phrases when these are emphatically contrasted, as in "Not the black house, the white house!"
- VandenBos, Gary R., ed. (2010). Publication Manual of the American Psychological Association (6th ed.). American Psychological Association. section 4.13. ISBN 1-4338-0559-6. "Hyphenation. Compound words take many forms. [...] The dictionary is an excellent guide for such decisions. [...] When a compound can be found in the dictionary, its usage is established and it is known as a permanent compound."
- The Chicago Manual of Style (16th ed.). University of Chicago Press. 2010. section 7.85. ISBN 978-0-226-10420-1. "In general, Chicago prefers a spare hyphenation style: if no suitable example or analogy can be found either in this section or in the dictionary, hyphenate only if doing so will aid readability"
- Merriam-Webster's Manual for Writers and Editors. Merriam Webster. 1998. p. 73. ISBN 978-0-87779-622-0. "Permanent compound adjectives are usually written as they appear in the dictionary even when they follow the noun they modify"
- The Chicago Manual of Style (16th ed.). University of Chicago Press. 2010. section 7.80. ISBN 978-0-226-10420-1. "Where no ambiguity could result, as in public welfare administration or graduate student housing, hyphenation is unnecessary"