s

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The 19th letter of the modern English alphabet.
• noun Any of the speech sounds represented by the letter s.
• noun The 19th in a series.
• noun Something shaped like the letter S.
• abbreviation second (unit of time)
• abbreviation Mathematics second (of arc)
• abbreviation stere
• abbreviation strange quark

from The Century Dictionary.

• The suffix of the possessive or genitive case singular, earlier -es, by syncope -s, now regularly written with an apostrophe, 's. See -es.
• The suffix of the plural form of nouns, earlier -es, which is now retained in pronunciation only after a sibilant, being otherwise reduced by syncope to -s. See -es.
• The suffix of the third person singular of the present indicative of verbs, earlier -es, more originally -eth, -th. See -eth, -th.
• The nineteenth letter and fifteenth consonant of the English alphabet, having a corresponding place also in the alphabets from which that is derived (the twenty-first, or last but one, in Phenician).
• As a medieval Roman numeral, 7; also 70; with a dash over it (S), 70,000.
• In chem., the symbol of sulphur.
• An abbreviation: Of Society in such combinations as F. R. S. (Fellow of the Royal Society), F. L. S. (Fellow of the Linnean Society), etc.
• Of Surgery, as in D. D. S. (Doctor of Dental Surgery).
• Of Science, as in B. S. (Bachelor of Science).
• Of South or Southern.
• Of Sunday and Saturday.
• [lowercase] Of Latin solidum, equivalent to English shilling: as, £ s. d., pounds, shillings, pence.
• In anatomy and zoology, of sacral: used in vertebral formulæ: as, S. 5, five sacral vertebræ.
• [lowercase] Of second (sixtieth part of a minute), substantive (a noun), snow (in a ship's log-book), of Latin semi, half (used in medical prescriptions after a quantity which is to be divided into two), and of spherical (of a lens).
• [lowercase] In heraldry, of sable.
• In meteorology, of stratus.
• In musical notation , of senza; in the form:S:, of segno (see D. S. and segno).
• An operative symbol in quaternions, signifying the operation of taking the scalar part of a quaternion.

from the GNU version of the Collaborative International Dictionary of English.

• the nineteenth letter of the English alphabet, is a consonant, and is often called a sibilant, in allusion to its hissing sound. It has two principal sounds; one a mere hissing, as in sack, this; the other a vocal hissing (the same as that of z), as in is, wise. Besides these it sometimes has the sounds of sh and zh, as in sure, measure. It generally has its hissing sound at the beginning of words, but in the middle and at the end of words its sound is determined by usage. In a few words it is silent, as in isle, débris. With the letter h it forms the digraph sh. See Guide to pronunciation, §§ 255-261.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun The nineteenth letter of the basic modern Latin alphabet.
• noun Symbol for second, an SI unit of measurement of time.
• noun voiceless alveolar fricative
• noun The nineteenth letter of the English alphabet, called ess and written in the Latin script.
• noun The ordinal number nineteenth, derived from this letter of the English alphabet, called ess and written in the Latin script.
• abbreviation sciences abbreviation for the second (unit of time in the International System of Units (SI))
• abbreviation metrology abbreviation for the scruple (unit of mass in the apothecaries' system)
• abbreviation Alternative form of s..

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun the 19th letter of the Roman alphabet
• noun 1/60 of a minute; the basic unit of time adopted under the Systeme International d'Unites
• noun (thermodynamics) a thermodynamic quantity representing the amount of energy in a system that is no longer available for doing mechanical work
• noun 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)
• noun the cardinal compass point that is at 180 degrees
• noun a unit of conductance equal to the reciprocal of an ohm