Etymology
Advertisement
eth (n.)
name of an Anglo-Saxon runic character (Ð, ð) representing the sound "-th-," 1846, from th + e, "the usual assistant vowel in letter-names" [Century Dictionary].
Related entries & more 
Advertisement
sloe (n.)

fruit of the blackthorn, Old English slah (plural slan), from Proto-Germanic *slaikhwon (source also of Middle Dutch sleeu, Dutch slee, Old High German sleha, German Schlehe), from PIE *sleiə- "blue, bluish, blue-black" (see livid).

The vowel has been influenced by that in the old plural form, which according to OED persisted into the 17c. Scottish slae preserves the older vowel. Sloe-eyed is attested from 1804; sloe gin first recorded 1878.

Related entries & more 
biennium (n.)
"space of two years," 1835, from Latin biennium "two years, a period of two years," from bi- "two" (see bi-) + annus "year" (see annual (adj.)). For vowel change, see biennial.
Related entries & more 
breakfast (n.)

"first meal of the day," mid-15c., from the verbal phrase; see break (v.) + fast (n.). For vowel shift, see below. An Old English word for it was undernmete (see undern), also morgenmete "morning meal."

Spanish almuerzo "lunch," but formerly and still locally "breakfast," is from Latin admorsus, past participle of admordere "to bite into," from ad "to" + mordēre "to bite" (see mordant). German Frühstück is from Middle High German vruostücke, literally "early bit."

In common with almuerzo, words for "breakfast" tend over time to shift in meaning toward "lunch;" compare French déjeuner "breakfast," later "lunch" (cognate of Spanish desayuno "breakfast"), from Vulgar Latin *disieiunare "to breakfast," from Latin dis- "apart, in a different direction from" + ieiunare, jejunare "fast" (see jejune; also compare dine). Greek ariston in Homer and Herodotus was a meal at the break of day but in classical times taken in the afternoon.

The long/short vowel contrast in break/breakfast represents a common pattern where words from Old English have a long vowel in their modern form but a short vowel as the first element of a compound: Christ/Christmas, holy/holiday, moon/Monday, sheep/shepherd, wild/wilderness, etc.

Related entries & more 
bramble (n.)
Old English bræmbel "rough, prickly shrub" (especially the blackberry bush), with euphonic -b- (which then caused the vowel to shorten), from earlier bræmel, from Proto-Germanic *bræmaz (see broom). Related: Brambleberry "blackberry" (late Old English).
Related entries & more 
Advertisement
omicron (n.)

15th letter of the Greek alphabet, c. 1400, literally "small 'o,' " from o + Greek (s)mikros "small" (see micro-). So called because the vowel was "short" in ancient Greek. Compare omega.

Related entries & more 
Mexico 

republic lying to the south of the U.S., from Spanish, from Nahuatl (Aztecan) mexihco, which originally referred to the Valley of Mexico around present-day Mexico City. It became the name of the nation (formerly New Spain) upon independence from Spain in 1821.

The etymology of this is opaque. Because of the difference in vowel length, it cannot be derived from ME-TL 'maguey.' The sequence XIH also differs in vowel length from XIC-TLI 'navel,' which has been proposed as a component element. The final element is locative -C(O). [Kartunnen]
Related entries & more 
sack (n.4)

"sherry," 1530s, an alteration of French (vin) sec "dry (wine)," from Latin siccus "dry" (see siccative). Originally of strong, light-colored wine from Spain and the Canaries. OED notes that the vowel is "not a normal development from the original 'seck.' "

Related entries & more 
indelible (adj.)
1520s, from Latin indelebilis "indelible, imperishable," from in- "not, opposite of, without" (see in- (1)) + delebilis "able to be destroyed," from delere "destroy, blot out" (see delete). Vowel change from -e- to -i- in English is late 17c. Related: Indelibly.
Related entries & more 
collide (v.)

"to strike together forcibly," 1620s, from Latin collidere "strike together," from assimilated form of com "with, together" (see com-) + laedere "to strike, injure by striking," which is of unknown origin. For Latin vowel change, see acquisition. Related: Collided; colliding.

Related entries & more 

Page 2