Etymology
Advertisement
thunder (n.)

mid-13c., from Old English þunor "thunder, thunderclap; the god Thor," from Proto-Germanic *thunraz (source also of Old Norse þorr, Old Frisian thuner, Middle Dutch donre, Dutch donder, Old High German donar, German Donner "thunder"), from PIE *(s)tene- "to resound, thunder" (source also of Sanskrit tanayitnuh "thundering," Persian tundar "thunder," Latin tonare "to thunder"). Swedish tordön is literally "Thor's din." The unetymological -d- also is found in Dutch and Icelandic versions of the word (compare sound (n.1)). Thunder-stick, imagined word used by primitive peoples for "gun," attested from 1904.

Related entries & more 
Advertisement
expound (v.)

mid-14c., expounen, expounden, "to explain or comment on, to reveal the meaning" (of Scripture, etc.), from Old French espondre "expound (on), set forth, explain," from Latin exponere "put forth, expose, exhibit; set on shore, disembark; offer, leave exposed, reveal, publish," from ex "forth" (see ex-) + ponere "to put, place" (see position (n.)); with unetymological -d developing in French (compare sound (n.1)). The usual Middle English form was expoune. General (non-theological) sense of "set forth, reveal, describe or tell" is from late 14c. Related: Expounded; expounding.

'In Englissh,' quod Pacience, 'it is wel hard, wel to expounen, ac somdeel I shal seyen it, by so thow understonde.' ["Piers Plowman," late 14c.]
Related entries & more 
safe (adj.)

c. 1300, sauf, "unscathed, unhurt, uninjured; free from danger or molestation, in safety, secure; saved spiritually, redeemed, not damned;" from Old French sauf "protected, watched-over; assured of salvation," from Latin salvus "uninjured, in good health, safe," which is related to salus "good health," saluber "healthful" (all from PIE *solwos from root *sol- "whole, well-kept"). For the phonological development of safe from sauf, OED compares gage from Old North French gauge.

From late 14c. as "rescued, delivered; protected; left alive, unkilled." The meaning "not exposed to danger" (of places, later of valuables) is attested from late 14c.; in reference to actions, etc., the meaning "free from risk," is recorded by 1580s. The sense of "sure, reliable, not a danger" is from c. 1600. The sense of "conservative, cautious" is from 1823. It has been paired alliteratively with sound (adj.) from c. 1300. In Middle English it also meant "in good health," also "delivered from sin or damnation." Related: Safeness.

Related entries & more 
gender (n.)
Origin and meaning of gender

c. 1300, "kind, sort, class, a class or kind of persons or things sharing certain traits," from Old French gendre, genre "kind, species; character; gender" (12c., Modern French genre), from stem of Latin genus (genitive generis) "race, stock, family; kind, rank, order; species," also "(male or female) sex," from PIE root *gene- "give birth, beget," with derivatives referring to procreation and familial and tribal groups.

Also used in Latin to translate Aristotle's Greek grammatical term genos. The grammatical sense is attested in English from late 14c. The unetymological  -d- is a phonetic accretion in Old French (compare sound (n.1)).

The "male-or-female sex" sense is attested in English from early 15c. As sex (n.) took on erotic qualities in 20c., gender came to be the usual English word for "sex of a human being," in which use it was at first regarded as colloquial or humorous. Later often in feminist writing with reference to social attributes as much as biological qualities; this sense first attested 1963. Gender-bender is from 1977, popularized from 1980, with reference to pop star David Bowie.

Related entries & more 
phoneme (n.)

"distinctive sound or group of sounds," 1889, from French phonème, from Greek phōnēma "a sound made, voice," from phōnein "to sound or speak," from phōnē "sound, voice" (from PIE root *bha- (2) "to speak, tell, say"). Related: Phonematic.

Related entries & more 
Advertisement
sone (n.)

unit of loudness, 1936, from Latin sonus "sound," from PIE root *swen- "to sound."

Related entries & more 
sonic (adj.)

1923, from Latin sonus "sound" (from PIE root *swen- "to sound") + -ic. Sonic boom is attested from 1952.

Related entries & more 
dissonant (adj.)

early 15c., dissonaunt, "at variance, disagreeing," from Old French dissonant (13c.) and directly from Latin dissonantem (nominative dissonans), present participle of dissonare "differ in sound," from dis- "apart" (see dis-) + sonare "to sound, make a noise" (from PIE root *swen- "to sound"). The meaning "discordant in sound, harsh" is from 1570s. Related: Dissonantly.

Related entries & more 
phonogram (n.)

1845, "a written symbol or graphic character representing the sound of the human voice," from phono- "sound, voice" + -gram "a writing, recording." From 1879 as "a sound recording produced by a phonograph." Related: Phonogramic.

Related entries & more 
sonogram (n.)

1956, from combining form of Latin sonus "sound" (from PIE root *swen- "to sound") + -gram. Related: Sonograph (1951).

Related entries & more 

Page 3