S (ĕs), 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.
Both the form and the name of the letter S are derived from the
Latin, which got the letter through the Greek from the
Phænician. The ultimate origin is Egyptian. S is etymologically
most nearly related to c, z, t, and r; as,
in ice, OE. is; E. hence, OE. hennes; E.
rase, raze; erase, razor; that, G.
das; E. reason, F. raison, L. ratio; E.
was, were; chair, chaise (see C, Z, T, and
R.).