definition of
S

[1] #1 S n. [second, sec, s] 1/60 of a minute; the basic unit of time adopted under the Systeme International d'Unites. wn

[2] #2 S n. [sulfur, sulphur, atomic number 16] an abundant tasteless odorless multivalent nonmetallic element; best known in yellow crystals; occurs in many sulphide and sulphate minerals and even in native form (especially in volcanic regions). wn

[3] #3 S n. [south, due south, southward] the cardinal compass point that is at 180 degrees. wn

[4] #4 S n. [mho, siemens, reciprocal ohm] a unit of conductance equal to the reciprocal of an ohm. wn

[5] #5 S n. [s] the 19th letter of the Roman alphabet. wn