Prime (symbol)

[4] As an angular measurement, 3° 5′ 30″ means 3 degrees, 5 arcminutes and 30 arcseconds.

In historical astronomical works, the triple prime was used to denote "thirds" (1⁄60 of an arcsecond)[5][6] and a quadruple prime ⁗ "fourths" (1⁄60 of a third of arc),[a] but modern usage has replaced this with decimal fractions of an arcsecond.

Primes are sometimes used to indicate minutes, and double primes to indicate seconds of time, as in the John Cage composition 4′33″ (spoken as "four thirty-three"), a composition that lasts exactly 4 minutes 33 seconds.

[8][better source needed] In mathematics, the prime is generally used to generate more variable names for similar things without resorting to subscripts, with x′ generally meaning something related to (or derived from) x.

[10] In molecular biology, the prime is used to denote the positions of carbon on a ring of deoxyribose or ribose.

The chemistry of this reaction demands that the 3′ OH be extended by DNA synthesis.

The prime symbol is used in combination with lower case letters in the Helmholtz pitch notation system to distinguish notes in different octaves from middle C upwards.

In some musical scores, the double prime ″ is used to indicate a length of time in seconds.

[b] Unicode and HTML representations of the prime and related symbols are as follows.

The "modifier letter prime" and "modifier letter double prime" characters are intended for linguistic purposes, such as the indication of stress or the transliteration of certain Cyrillic characters.

[citation needed] In a context when the character set used does not include the prime or double prime character (e.g., in an online discussion context where only ASCII or ISO 8859-1 [ISO Latin 1] is expected), they are often respectively approximated by ASCII apostrophe (U+0027) or quotation mark (U+0022).