Definition of "S"

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

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

Initialism of south.  examples

Initialism of season (group of episodes of a series).  examples

(usually clothing, singular only) Initialism of small (the manufactured size or an item of that size).  examples

(music) Initialism of soprano.  examples

(American Library Association) Initialism of sextodecimo (book size, 15-17.5 cm in height).  examples

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

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