Etymology
Advertisement
theta (n.)
eighth letter of the Greek alphabet; in ancient Greece, from Hebrew teth; originally an aspirated -t- (see th). Written on ballots to indicate a vote for a sentence of "death" (thanatos), hence occasional allusive use for "death."
Related entries & more 
Advertisement
Morse code (n.)

character encoding system originally invented for use with the telegraph, by 1860, earlier Morse key (1858), so called in honor of Samuel F.B. Morse (1791-1872), U.S. inventor who produced a system of telegraphic communication in 1836. He invented both the recording telegraph and the alphabet of dots and dashes.

Related entries & more 
Cadmean victory (n.)

c. 1600, "victory involving one's own ruin," translating Greek Kadmeia nikē, from Cadmus (Greek Kadmos), legendary hero-founder of Thebes in Boeotia and bringer of the original sixteen-letter alphabet to Greece. Probably a reference to the story of Cadmus and the "Sown-Men," who fought each other till only a handful were left alive. Compare Pyrrhic (adj.1).

Related entries & more 
upsilon (n.)
20th letter of the Greek alphabet, 1640s, from Greek u psilon, literally "a mere (or bare) 'u;' " so called in later Greek in reference to its sound. The exact reason is variously explained, but it seems to have had something to do with distinguishing it from diphthongs.
Related entries & more 
T 

twentieth letter of the English alphabet; in the Phoenician alphabet the corresponding sign was the 22nd and last; everything after T in the modern alphabet represents European alterations or additions. The sound has been consistent throughout its history.

In Late Latin and Old French, -t- before -e- and -i- acquired the "s" value of -c- and words appeared in both spellings (nationem/nacionem) and often passed into Middle English with a -c- (nacioun). In most of these the spelling was restored to a -t- by or in the period of early Modern English, but sorting them out took time (Edmund Coote's "English Schoole-maister" (1596) noted malicious/malitious) and a few (space, place, coercion, suspicion) resisted the restoration. 

To cross one's t's(and dot one's i's) "to be exact" is attested from 1849. Phrase to a T "exactly, with utmost exactness" is recorded from 1690s, though the exact signification remains uncertain despite much speculation. The measuring tool called a T-square (sometimes suggested as the source of this) is recorded by that name only from 1785. The T-cell (1970) so called because they are derived from the thymus. As a medieval numeral, T represented 160. A T was formerly branded on the hand of a convicted thief.

Related entries & more 
Advertisement
Glagolitic (n.)
1861, with -itic + Serbo-Croatian glagolica "Glagolitic alphabet," from Old Church Slavonic glagolu "word," from PIE *gal-gal-, reduplicated form of root *gal- "to call, shout." The older of the two Slavic writing systems (Cyrillic is the other), used in Istria and Dalmatia, it was designed by Cyrillus c.863 C.E.
Related entries & more 
zed (n.)

"the name of the letter Z in the alphabet," c. 1400, probably from Old French zede, from Late Latin zeta, from Greek zēta, from Hebrew zayin, letter name, literally "weapon;" so called in reference to the shape of this letter in ancient Hebrew. U.S. pronunciation zee is first attested 1670s. Other dialectal names for the letter are izzard, ezod, uzzard, and zod.

Related entries & more 
iota (n.)
"very small amount," 1630s, figurative use of iota, ninth and smallest letter in the Greek alphabet (corresponding to Latin -i-). Its use in this sense is after Matthew v.18 (see jot (n.), which is the earlier form of the name in English), but iota in classical Greek also was proverbially used of anything very small. The letter name is from Semitic (compare Phoenician and Hebrew yodh).
Related entries & more 
gamma 
third letter of the Greek alphabet, c. 1400, from Greek gamma, from Phoenician gimel, said to mean literally "camel" (see camel) and to be so called for a fancied resemblance of its shape to some part of a camel. Gamma rays (1903) originally were thought to be a third type of radiation, but later were found to be very short X-rays.
Related entries & more 
crisscross (n.)

also criss-cross, 1833, "a checked pattern in cloth," 1848, "a crossing or intersection," from Middle English crist(s)-crosse (early 15c.), earlier Cristes-cros (c. 1200) "the Cross of Christ," also "the sign of the cross," from late 14c. often "referring to the mark of a cross formerly written before the alphabet in hornbooks. The mark itself stood for the phrase Christ-cross me speed ('May Christ's cross give me success'), a formula said before reciting the alphabet" [Barnhart]. It has long been used without awareness of its origin.

How long agoo lerned ye, 'Crist crosse me spede!'
Have ye no more lernyd of youre a b c,
[Lydgate, "The Prohemy of a Marriage Betwix an Olde Man and a Yonge Wife," c. 1475]

It is attested from 1860 as an old name for tic-tac-toe. As an adjective, by 1846. As a verb, by 1818. 

Related entries & more 

Page 4