A dvandva (Sanskrit द्वन्द्व dvandva 'pair') or twin or Siamese linguistic compound refers to one or more objects that could be connected in sense by the conjunction 'and', where the objects refer to the parts of an agglomeration described by the compound. Dvandvas are common in some languages such as Sanskrit where the term originates, as well as Chinese, Japanese, and some Modern Indic languages such as Hindi and Urdu, but less common in English (the term is not often found in English dictionaries).
Examples include Sanskrit mātāpitarau (मातापितरौ) for 'mother and father'; Chinese shānchuān and Japanese yamakawa (山川) for 'mountains and rivers'; Modern Greek "maxeropiruno" (μαχαιροπήρουνο) for 'fork and knife', "anðrojino" (ανδρόγυνο) for "married couple (lit. man-woman)", "benovjeno" (μπαινοβγαίνω) for 'go in and out'.
Note such compounds as singer-songwriter, in the sense 'someone who is both a singer and a songwriter' are not dvandva compounds. Within the Sanskrit classification of compounds these are considered कर्मधारय karmadhāraya compounds such as राजर्षि rājarṣi 'king-sage,' i.e. 'one who is both a king and a sage' (राजा चासावृषिश्च).
There are two or three kinds of dvandva compounds in Sanskrit, depending on classification.
The first, and most common kind, the itaretara dvandva, is an enumerative compound word, the meaning of which refers to all its constituent members. The resultant compound word is in the dual or plural number, depending on the total number of described individuals. It takes the gender of the final member in the compound construction. Examples:
- रामलक्ष्मणौ rāma-lakṣmaṇau (dual) 'Rama and Lakshmana'
- हरिहरौ hari-harau (dual) 'Hari and Hara'
- आचार्यशिष्यौ ācārya-śiṣyau (dual) 'teacher and student'
- रामलक्ष्मणभरतशत्रुघ्नाः rāma-lakṣmaṇa-bharata-śatrughnāh (plural) 'Rama, Lakshmana, Bharata and Satrughna'
- नराश्वरथदन्तिनः nar-āśva-ratha-dantinaḥ (plural) 'men, horses, chariots, and elephants'
- देवमनुष्याः deva-manuṣyāḥ (plural) 'gods and humans'
(compare Greek Avaróslavi (Αβαρόσλαβοι) "the Avars and the Slavs (two distinct tribes acting as a unit)", similarly with case and number marking displayed only on the last part of the compound, the first having the form of the word root)
Itaretaras formed from two kinship terms behave differently, in that the first word is not in the compound form but in the nominative (singular).
- मातापितरौ mātā-pitarau 'mother and father'
The second, rarer kind is called samāhāra dvandva and is a collective compound word, the meaning of which refers to the collection of its constituent members. The resultant compound word is in the singular number and is always neuter in gender. Examples:
- pāṇipādam 'limbs', literally 'hands and feet', from pāṇi 'hand' and pāda 'foot'
Compare Modern Greek andróyino ανδρόγυνο "husband and wife" or maxeropíruno μαχαιροπίρουνα "cutlery" (literally "knife-forks"), similarly always in the neuter singular (plural marking would refer to several couples or cutlery sets).
According to some grammarians, there is a third kind of dvandva, called ekaśeṣa dvandva or residual compound. It is formed like a itaretara, but the first constituent is omitted. The remaining final constituent still takes the dual (or plural) number. According to other grammarians, however, the ekaśeṣa is not properly a compound at all. An example:
- pitarau 'parents', from mātā 'mother' + pitā 'father'