(on pronouns) Possessive marker, indicating that an object belongs to the word bearing the marker. / (on nouns, now nonstandard) Alternative form of -'s

Used in the formation of certain English adverbs.

Contraction of is. / Contraction of has. / (proscribed, dialectal, Southern US) Contraction of was.

plural of A+

(organic chemistry) secondary form

(physics) subatomic particles with a spin (quantum angular momentum) of 0, predicted by supersymmetry; the bosonic equivalent of known fermions

(usually clothing) Initialism of small (of the manufactured size).

The nineteenth letter of the English alphabet, called ess and written in the Latin script.

The ordinal number nineteenth, derived from this letter of the English alphabet, called ess and written in the Latin script.

(set theory) An axiomatic set theory, developed by logician George Boolos, in which several of the axioms of ZF are derivable as theorems.