S2Pronunciation: /ɛs/Translate S | into French | into German | into Italian | into Spanish Definition of S abbreviation (chiefly in Catholic use) Saint:S Ignatius Loyola siemens. small (as a clothes size). South or Southern:65° S Biochemistry Svedberg unit(s). Sweden (international vehicle registration). symbol the chemical element sulphur. Chemistry entropy. S in other Oxford dictionaries Definition of S in the US English dictionary