fourth letter of the Roman alphabet, from Greek delta, from Phoenician and Hebrew daleth, pausal form of deleth "door," so called from its shape. The form of the modern letter is the Greek delta (Δ) with one angle rounded. As the sign for "500" in Roman numerals, it is said to be half of CIƆ, which was an early form of M, the sign for "1,000." 3-D for "three-dimensional" is attested from 1952.
13th letter of the English alphabet, from Greek mu, from Semitic mem. It represents a very stable and unchanging sound in Indo-European, described by Johnson as "a kind of humming inward." The Roman symbol for 1,000; sometimes used in this sense in English 15c.-16c.; but in late 20c. newspaper headlines it stands for million. As a thickness of type, from 1680s (commonly spelled out, em).
final letter of the Greek alphabet, c. 1400, from Medieval Greek omega, from classical Greek o mega "big 'o' " (in contrast to o micron "little 'o' "); so called because the vowel was long in ancient Greek. From o + megas "great, large, vast, big, high, tall; mighty, important" (from PIE root *meg- "great"). Used figuratively for "the last, the final" of anything (as in Revelation i.8) from 1520s.
c. 1200, name of the fourth letter of the Greek alphabet (equivalent to our D), which was shaped like a triangle. The name is from Phoenician daleth "tent door." Sense of "triangular island or alluvial tract between the diverging branches of the mouth of a great river" is because Herodotus used it of the delta-shaped mouth of the Nile. It was so used in English from 1550s and applied to other river mouths, of whatever shape, by 1790. Related: Deltaic; deltification.
not in the Roman alphabet, but the Modern English sound it represents is close to the devocalized consonant expressed by Roman -U- or -V-. In Old English, this originally was written -uu-, but by 8c. began to be expressed by the runic character wyn (Kentish wen), which looked like this: ƿ (the character is a late addition to the online font set and doesn't display properly on many computers, so it's something like a combination of lower-case -p- and a reversed -y-).
In 11c., Norman scribes introduced -w-, a ligatured doubling of Roman -u- which had been used on the continent for the Germanic "w" sound, and wyn disappeared c. 1300. -W- is not properly a letter in the modern French alphabet, and it is used there only in borrowed foreign words, such as wagon, weekend, Western, whisky, wombat. Charles Mackay ("Extraordinary Popular delusions and the Madness of Crowds") reports that the Scotsman John Law, author of the Mississippi stock swindle of 1720, was known in France as Monsieur Lass "to avoid the ungallic sound, aw."
proprietary name of a brand of canvas sneakers, 1917, registered by United States Rubber Co., N.Y. Based on Latin ped-, stem of pes "foot" (see foot (n.))
"We wanted to call it Peds, but ... it came too close to ... other brand names. So we batted it around for awhile and decided on the hardest-sounding letter in the alphabet, K, and called it Keds, that was in 1916." [J.Healey, in R.L. Cohen, "Footwear Industry," x.93]
first letter of the Roman alphabet, based on Greek alpha (see alpha). In music from c. 1600 as the name of the sixth note of the natural scale; it is the note given by a fixed-tone instrument (usually oboe or organ) to which all the instruments of an orchestra are tuned. As a blood type, 1926, denoting A agglutinogens. The A side of a two-sided record (by 1962, see side (n.)) held the material chosen for promotion. A-bomb, short for atom bomb, was in newspaper headlines by Aug. 8, 1945.