s

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. The 19th letter of the modern English alphabet.
2. n. Any of the speech sounds represented by the letter s.
3. n. The 19th in a series.
4. n. Something shaped like the letter S.
5. abbr. second (unit of time)
6. abbr. Mathematics second (of arc)
7. abbr. stere.
8. abbr. strange quark

Century Dictionary and Cyclopedia

1. 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). The historical exhibit of related forms, as given for the other letters (see especially A), is as follows:
2. As a medieval Roman numeral, 7; also 70; with a dash over it (S), 70,000.
3. In chem., the symbol of sulphur.
4. 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.
5. Of Surgery, as in D. D. S. (Doctor of Dental Surgery).
6. Of Science, as in B. S. (Bachelor of Science).
7. Of South or Southern.
8. Of Sunday and Saturday.
9. [lowercase] Of Latin solidum, equivalent to English shilling: as, £ s. d., pounds, shillings, pence.
10. In anatomy and zoology, of sacral: used in vertebral formulæ: as, S. 5, five sacral vertebræ.
11. [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).
12. [lowercase] In heraldry, of sable.
13. In meteorology, of stratus.
14. In musical notation , of senza; in the form:S:, of segno (see D. S. and segno).
15. An operative symbol in quaternions, signifying the operation of taking the scalar part of a quaternion. It is also used in algebra for certain varieties of summation. The lower-case s usually denotes space, or the length of the arc of a curve. An s below the line, in enumerative geometry, refers to a plane pencil of rays. Σ (Greek S) signifies the sum of successive values of a function; the variable which is to take successive integral values in the terms to be added may be written below the line after the Σ, and the lower and upper limit of the summation may be written below and above the Σ. Thus, In the calculus of finite differences Σ is used like a sign of indefinite integration, the lower limit being replaced by an arbitrary constant, while the upper is supposed to be 1 less than the value of the variable. Thus, Σ Fx = F (x-1) + F (x-2) + etc., down to a constant value of the variable, and then an arbitrary constant is to be added to the series. σ is used in the integral calculus to denote the area of a surface. A modified long s, f, is the sign of integration.
16. The suffix of the possessive or genitive case singular, earlier -es, by syncope -s, now regularly written with an apostrophe, 's. See -es.
17. 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.
18. The suffix of the third person singular of the present indicative of verbs, earlier -es, more originally -eth, -th. See -eth, -th.

Wiktionary

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

GNU Webster's 1913

1. 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.

WordNet 3.0

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