Definitions
1.NounThe result of shortening or reducing; abridgment. .mw-parser-output .defdate{font-size:smaller}
2.NounA shortened or contracted form of a word or phrase used to represent the whole, using omission of letters, and sometimes substitution of letters, or duplication of initial letters to signify plurality, including signs such as +, =, @. (The addition of quotations indicative of this usage is being sought:)"Hants is an abbreviation of Hampshire."
3.NounThe process of abbreviating.
4.NounA notation used in music score to denote a direction, as pp or mf.
5.NounOne or more dashes through the stem of a note, dividing it respectively into quavers, semiquavers, demisemiquavers, or hemidemisemiquavers.
6.NounAny convenient short form used as a substitution for an understood or inferred whole.
7.NounLoss during evolution of the final stages of the ancestral ontogenetic pattern.
8.NounReduction to lower terms, as a fraction.