Used to form regular plurals of nouns. / Used to form many pluralia tantum (nouns that are almost or entirely without singular forms).

The nineteenth 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.

plural of A+

plural of A*

plural of A*

Maintenance service provided after the sale of a product

Possessive marker, indicating that an object belongs to the noun or noun phrase bearing the marker. / In the absence of a specified object, used to indicate “the house/place/establishment of”.

(sometimes proscribed) Used to form the plurals of numerals, letters, some abbreviations and some nouns, usually because the omission of an apostrophe would make the meaning unclear or ambiguous.

Genitival interfix used to link elements in some compounds, equivalent to the possessive clitic -'s.