- Any convenient short form used as a substitution for an understood or inferred whole.
- (linguistics) A shortened or contracted form of a word or phrase, used to represent the whole, utilizing omission of letters, and sometimes substitution of letters, or duplication of initial letters to signify plurality, including signs such as, +, =, @. [Late 16th century.]
- (music) One or more dashes through the stem of a note, dividing it respectively into quavers, semiquavers, demisemiquavers, or hemidemisemiquavers.
- (mathematics) Reduction to lower terms, as a fraction.
- The result of shortening or reducing; abridgment. [First attested around 1350 to 1470.]
- (music) A notation used in music score to denote a direction, as pp or mf.
- (biology) Loss during evolution of the final stages of the ancestral ontogenetic pattern.
- The process of abbreviating. [Mid 16th century.]