Anniversary

For other uses, see Anniversary (disambiguation).

On the 40th anniversary of his reign, King Carl XVI Gustaf of Sweden toasts the city's Mayor in front of Stockholm Palace.

Memorial plaque presented by the National Capital Sesquicentennial Commission, 1951

An anniversary is the date on which an event took place or an institution was founded in a previous year, and may also refer to the commemoration or celebration of that event. For example, the first event is the initial occurrence or, if planned, the inaugural of the event. One year later would be the first anniversary of that event. The word was first used for Catholic feasts to commemorate saints.

Most countries celebrate national anniversaries, typically called national days. These could be the date of independence of the nation or the adoption of a new constitution or form of government. The important dates in a sitting monarch's reign may also be commemorated, an event often referred to as a "jubilee".

Anniversary names

• Birthdays are the most common type of anniversary, on which someone's birthdate is commemorated each year. The actual celebration is sometimes moved for practical reasons, as in the case of an official birthday.
• Wedding anniversaries are also often celebrated, on the same day of the year as the wedding occurred.
• Death anniversaries.

The Latin phrase dies natalis (literally "birth day") has become a common term, adopted in many languages, especially in intellectual and institutional circles, for the anniversary of the founding ("legal or statutory birth") of an institution, such as an alma mater (college or other school). In ancient Rome, the [dies] Aquilae natalis was the "birthday of the eagle", the anniversary of the official founding of a legion.

Anniversaries of nations are usually marked by the number of years elapsed, expressed with Latin words or Roman numerals.

Latin-derived numerical names

Latin terms for anniversaries are mostly straightforward, particularly those relating to the first twenty years (1–20), or multiples of ten years (30, 40, 60, 70 etc.), or multiples of centuries or millennia (100, 200, 300, 1000, 2000, 3000, etc.) In these instances, the name of the anniversary is generally derived from the Latin word(s) for the respective number of years. However, when anniversaries relate to fractions of centuries (125, 150, 175, 250 years—i.e. 1.25, 1.5, 1.75, and 2.5 centuries), the situation is not as simple.

Roman fractions were based on a duodecimal system. From 1⁄12 to 8⁄12 they were expressed as multiples of twelfths (uncia "twelfth"; the source of the English words inch and ounce) and from 9⁄12 to 11⁄12 they were expressed as multiple twelfths less than the next whole unit—i.e. a whole unit less 3⁄12, 2⁄12 or 1⁄12 respectively. There were also special terms for quarter (quadrans), half (semis), and three-quarters (dodrans). Dodrans is a Latin contraction of de-quadrans which means "a whole unit less a quarter" (de means "from"; quadrans means "quarter"). Thus for the example of 175 years, the term is a quarter century less than the next whole (bi)century or 175 = (−25 + 200).

In Latin, it seems that this rule did not apply precisely for 1½. While secundus is Latin for "second", and bis for "twice", these terms are not used such as in sesqui-secundus. Instead sesqui (or ses) is used by itself.

Anniversary	Latin-derived term	Other terms	Comments
½ yearly	Semiannual	Biannual	i.e. twice a year as opposed to biennial = every second year
1 year	Annual	Paper
2 years	Biennial	Cotton	i.e. in alternate years as opposed to biannual = twice a year
3 years	Triennial	Leather
4 years	Quadrennial	Linen
5 years	Quinquennial	Wood
6 years	Sexennial	Iron
7 years	Septennial	Wool
8 years	Octennial	Bronze
9 years	Novennial	Copper
10 years	Decennial	Tin/Aluminium
11 years	Undecennial	Steel
12 years	Duodecennial	Silk
13 years	Tredecennial	Lace
14 years	Quattuordecennial	Ivory
15 years	Quindecennial	Crystal
20 years	Vigintennial / Vicennial	China/Porcelain
25 years	Quadranscentennial	Silver jubilee
10000 days (approx 27.4 years)		Myriad
30 years		Pearl jubilee
40 years	Quadragennial	Ruby jubilee
50 years	Semicentennial / Quinquagenary	Golden jubilee
60 years	Sexagennial / Sexagenary	Diamond jubilee
65 years		Sapphire jubilee
70 years	Septuagennial	Platinum jubilee
75 years	Semisesquicentennial	Palladium jubilee
100 years	Centennial / Centenary
125 years	Quasquicentennial		Term is broken down as quasqui- (and a quarter) centennial (100 years). Quasqui is a contraction from quadrans "a quarter" plus the clitic conjunction -que "and". The term was coined by Funk and Wagnalls editor Robert L. Chapman in 1961.
150 years	Sesquicentennial		Term broken down as sesqui- (one and a half) centennial (100 years)
175 years	Dodransbicentennial		Dodrans is a Latin contraction of de-quadrans which means "a whole unit less a quarter" (de means "from"; quadrans means "quarter"). 175 years is a quarter century less than the next whole (bi)century or 175 = (−25 + 200).
		Dodrabicentennial	Alternative Latin form of Dodransbicentennial
		Dequasbicentennial	Alternative Latin form of Dodransbicentennial
		Dosquicentennial	Dosquicentennial has been used in modern times and this is perhaps a modern contraction of "de-quadrans". However, it seems inappropriate to combine the terms que and de when dealing with such Roman fractions. In any event, if such a conjunction was appropriate then it would perhaps more likely have been "Dosquibicentennial" (but the result is little shorter anyway).
		Demisemiseptcentennial	Probably a modern coined term: demisemiseptcentennial; literally one-half (demi-) × one-half (semi-) × seven (sept-) × 100 years (centennial)—also demisemiseptcentenary.
		Quartoseptcentennial	Probably a modern coined term: quartoseptcentennial; literally one-quarter (quarto-) × seven (sept-) × 100 years (centennial)—also quartoseptcentenary.
		Terquasquicentennial	First used by Bell Laboratories in celebrating its 175th anniversary as a corporation. Is a coined word for an anniversary of 175 years, but the elements of the word literally refer to an anniversary of 375 years, as follows: ter- (3) × quasqui- (1¼) × centennial (100 years)
		Septaquintaquinque- centennial	Suggested by lexicographer Robert L. Chapman to William Safire; first appeared in Safire's column, "On Language" (The New York Times Magazine, February 12, 1995). It is a coined word for an anniversary of 175 years, but the elements of the word literally refer to an anniversary of 35,000 years, as follows: septaquinta- (70) × quinque- (5) × centennial (100 years)
200 years	Bicentennial	Bicentenary
250 years	Sestercentennial	-	To express 2½ in Latin it would be expressed as "half-three". The term relates to being halfway [from the second] to the third integer. In Latin this is "Sestertius" which is a contraction of semis (halfway) tertius (third)—hence Sestercentennial.
		Semiquincentennial	Probably a modern coined term: semi- (half) × quin (5) × centennial (100 years) = 250 years. Used by Brown University in 2015.
		Bicenquinquagenary	Used by Princeton University in 1996, Reading, Pennsylvania in 1998, and Washington and Lee University in 1999. It is a coined word for an anniversary of 250 years: bi- (2) × cen(t)- (100) + quinquagenary (50 years).
		Quarter-millennial	Meaning one quarter of one thousand years.
300 years	Tercentenary / Tricentenary	Tercentennial / Tricentennial
350 years	Sesquarcentennial		A modern coined term; sesquarcentennial for 350 years is deduced here from the "Sestertius" definition for 250 years above. For 350 years it relates to being halfway from the third to the fourth integer; thus a contraction of semis (halfway) and quartus (fourth); hence Sesquarcentennial.
		Semiseptcentennial	Probably a modern coined term: semi- (half) × sept (7) × cen(t)- (100) × centennial (350 years)
400 years	Quadricentennial	Quadricentenary / Quatercentenary
500 years	Quincentenary	Quincentennial
600 years	Sexcentenary	Sexacentennial
700 years	Septcentennial	Septuacentennial	Probably a coined term; earliest known use in March 1988. Chiang Mai Septcentennial Stadium (Chiang Mai, Thailand) was completed in 1991.
800 years	Octocentenary	Octocentennial
900 years	Nonacentennial
1000 years	Millennial
1500 years	Sesquimillennial		Term broken down as sesqui- (one and a half) millennial (1000 years)
2000 years	Bimillennial
3000 years	Trimillennial
10,000 years	Decamillennial

Anniversary symbols

Many anniversaries have special names. Etiquette in Society, in Business, in Politics and at Home by Emily Post, published in 1922, contained suggestions for wedding anniversary gifts for 1, 5, 10, 15, 20, 25, 50, and 75 years. Wedding anniversary gift suggestions for other years were added in later editions and publications; they now comprise what is referred to as the "traditional" list. Generally speaking, the longer the period, the more precious or durable the material associated with it. See wedding anniversary for a general list of the wedding anniversary symbols; however, there are variations according to some national traditions.

Furthermore, there exist numerous partially overlapping, partially contradictory lists of anniversary gifts (such as wedding stones), separate from the 'traditional' names.

The concepts of a person's birthday stone and zodiac stone, by contrast, are fixed for life according to the day of the week, month, or astrological sign corresponding to the recipient's birthday.

See also

• List of historical anniversaries
• Quinquennial Neronia
• Wedding anniversary