foetusyoudaoicibaDictYouDict[foetus 词源字典]
foetus: [14] Foetus comes from Latin fētus ‘giving birth, offspring’, which also gave English fawn ‘young deer’. It was a noun use of the adjective fētus ‘pregnant, productive’, from whose derivative effētus English got effete. Probably it was related to Latin fēcundas (source of English fecund [14]) and fēlīx ‘happy’ (whence English felicity), and there could even be etymological links with fēmina ‘woman’, from which English gets feminine and female.
=> effete, fecund, felicity[foetus etymology, foetus origin, 英语词源]
impetuousyoudaoicibaDictYouDict
impetuous: [14] Etymologically, impetuous means ‘having impetus’. It comes from Latin impetuōsus, a derivative of the noun impetus ‘attack’ (source of English impetus [17]), which in turn was based on impetere ‘attack’. This was a compound verb formed from the prefix in- ‘against’ and petere ‘go towards, seek, attack’ (source of English appetite, compete, perpetuate, petition, petulant, and repeat).

The etymological idea underlying both words is thus of ‘rushing towards something with great violence or aggression’. Another member of the same family is impetigo [16], the name of a sort of skin disease. This was borrowed from Latin impetīgō, whose medical meaning was a specialization of an earlier and much more general ‘attack’ (as in ‘an attack of eczema’).

=> appetite, compete, impetus, perpetuate, petulant, repeat
perpetualyoudaoicibaDictYouDict
perpetual: see repeat
petulantyoudaoicibaDictYouDict
petulant: see repeat
petuniayoudaoicibaDictYouDict
petunia: see tobacco
returnyoudaoicibaDictYouDict
return: [14] The origins of return are in Vulgar Latin. There, Latin tornāre (source of English turn), which originally meant ‘turn on a lathe’, was combined with the prefix re- ‘back’ to produce *retornāre ‘turn back’, which passed via Old French retorner into English as return.
=> turn
arboretum (n.)youdaoicibaDictYouDict
"tree-garden," 1838, from Latin arboretum, literally "a place grown with trees," from arbor "tree," which is of unknown origin, + -etum, suffix used to form the names of gardens and woods.
Betula (n.)youdaoicibaDictYouDict
genus of the birches, from Latin betula "birch," from Gaulish betu- "bitumen" (cognates: Middle Irish beithe "box tree," Welsh bedwen "birch tree"). According to Pliny, so called because the Gauls extracted tar from birches. Birch tar is still sold as an analgesic and stimulant and made into birch beer by the Pennsylvania Dutch.
consuetude (n.)youdaoicibaDictYouDict
late 14c., from Middle French consuetude, from Latin consuetudo, from consuetus, past participle of consuescere "to accustom" (see custom).
desuetude (n.)youdaoicibaDictYouDict
1620s, from Middle French désuétude (16c.), from Latin desuetudo "disuse," from desuetus, past participle of desuescere "become unaccustomed to," from de- "away, from" (see de-) + suescere "become used to" (see mansuetude).
disquietude (n.)youdaoicibaDictYouDict
1709; from disquiet on model of quietude.
etude (n.)youdaoicibaDictYouDict
a composition having musical value but primarily intended to exercise the pupil in technical difficulties, 1837, from French étude, literally "study" (12c., Old French estudie), from Latin studium (see study (n.)). Popularized in English by the etudes of Chopin (1810-1849).
etui (n.)youdaoicibaDictYouDict
1610s, also ettuy, etwee from French étui, Old French estui (12c.) "case, box, container," back-formation from estuier "put in put aside, spare; to keep, shut up, imprison," which is of uncertain origin. Perhaps from Latin studere "to be diligent."
fetus (n.)youdaoicibaDictYouDict
late 14c., "the young while in the womb or egg" (tending to mean vaguely the embryo in the later stage of development), from Latin fetus (often, incorrectly, foetus) "the bearing or hatching of young, a bringing forth," from Latin base *fe- "to generate, bear," also "to suck, suckle" (see fecund).

In Latin, fetus sometimes was transferred figuratively to the newborn creature itself, or used in a sense of "offspring, brood" (as in Horace's "Germania quos horrida parturit Fetus"), but this was not the basic meaning. It also was used of plants, in the sense of "fruit, produce, shoot," and figuratively as "growth, production." The spelling foetus is sometimes attempted as a learned Latinism, but it is not historic.
foetus (n.)youdaoicibaDictYouDict
see fetus; for spelling, see oe.
hebetude (n.)youdaoicibaDictYouDict
1620s, from Latin hebetudo, noun of quality from hebes "blunt, dull," of unknown origin. Related: Hebetate (v.); hebetation; hebetudinous.
impetuosity (n.)youdaoicibaDictYouDict
early 15c., "violent movement, rushing," from Old French impetuosité (13c.), from Medieval Latin impetuositatem (nominative impetuositas), from Late Latin impetuosus (see impetuous).
impetuous (adj.)youdaoicibaDictYouDict
late 14c., "hot-tempered, fierce," from Old French impetuos (13c.) and directly from Late Latin impetuosus "impetuous, violent," from Latin impetus "attack" (see impetus). Related: Impetuously; impetuousness.
impetus (n.)youdaoicibaDictYouDict
early 15c., impetous "rapid movement, rush;" 1640s, with modern spelling, "force with which a body moves, driving force," from Latin impetus "attack, assault, onset, impulse, violence, vigor, force, passion," related to impetere "to attack," from assimilated form of in- "into, in, on, upon" (see in- (2)) + petere "aim for, rush at" (see petition (n.)).
mansuetude (n.)youdaoicibaDictYouDict
"tameness, gentleness, mildness," late 14c., from Latin mansuetudo "tameness, mildness, gentleness," noun of state from past participle stem of mansuescere "to tame," literally "to accustom to the hand," from manus "hand" (see manual (adj.)) + suescere "to accustom, habituate," from PIE *swdh-sko-, from *swedh- (see sodality), extended form of root *s(w)e- (see idiom).
non-returnable (adj.)youdaoicibaDictYouDict
1903, from non- + returnable.
perpetual (adj.)youdaoicibaDictYouDict
mid-14c., from Old French perpetuel "without end" (12c.) and directly from Latin perpetualis "universal," in Medieval Latin "permanent," from perpetuus "continuous, universal," from perpetis, genitive of Old Latin perpes "lasting," probably from per- "through" + root of petere "to seek, go to, aim at" (see petition (n.)). Related: Perpetually. Perpetual motion is attested from 1590s.
perpetuate (v.)youdaoicibaDictYouDict
1520s, a back-formation from perpetuation or else from Latin perpetuatus, past participle of perpetuare "to make perpetual," from perpetuus (see perpetual). Related: Perpetuated; Perpetuating.
perpetuation (n.)youdaoicibaDictYouDict
late 14c., from Medieval Latin perpetuationem (nominative perpetuatio), noun of action from past participle stem of perpetuare (see perpetuate).
perpetuity (n.)youdaoicibaDictYouDict
late 14c., from Old French perpetuité "permanence, duration" (13c., Modern French perpétuité) and directly from Latin perpetuitatem (nominative perpetuitas) "uninterrupted duration, continuity, continuous succession," from perpetuus (see perpetual).
perpetuous (adj.)youdaoicibaDictYouDict
"perpetual," 1610s, from Latin perpetuus "continuous, unbroken, uninterrupted" (see perpetual).
petulance (n.)youdaoicibaDictYouDict
c. 1600, "insolence, immodesty," from French pétulance (early 16c.), from Latin petulantia "sauciness, impudence," noun of quality from petulantem (see petulant). Meaning "peevishness" is recorded from 1784, from influence of pettish, etc. It displaced earlier petulancy (1550s).
petulant (adj.)youdaoicibaDictYouDict
1590s, "immodest, wanton, saucy," from Middle French petulant (mid-14c.), from Latin petulantem (nominative petulans) "wanton, froward, saucy, insolent," present participle of petere "to attack, assail; strive after; ask for, beg, beseech" (see petition (n.)). Meaning "peevish, irritable" first recorded 1775, probably by influence of pet (n.2). Related: Petulantly.
petunia (n.)youdaoicibaDictYouDict
1825, from Modern Latin Petunia (1789), from French petun (16c.), an obsolete word for "tobacco plant," from Portuguese petum, evidently from Guarani (Paraguay) pety. The petunia has a botanical affinity to the tobacco plant. See tobacco.
quietude (n.)youdaoicibaDictYouDict
1590s, from Middle French quiétude (c. 1500) or directly from Late Latin quietudo, from Latin quietus (see quiet (n.)).
quietus (n.)youdaoicibaDictYouDict
"discharge, clearing of accounts," 1530s, short for Medieval Latin phrase quietus est "he is quit" (see quit). Hence, "death" (i.e. "final discharge"), c. 1600. Latin quies also was used for "the peace of death."
retune (v.)youdaoicibaDictYouDict
also re-tune, c. 1600 of musical instruments; 1974 of engines, from re- + tune (v.). Related: Retuned; retuning.
return (v.)youdaoicibaDictYouDict
early 14c., "to come back, come or go back to a former position" (intransitive), from Old French retorner "turn back, turn round, return" (Modern French retourner), from re- "back" (see re-) + torner "to turn" (see turn (v.)). Transitive sense of "report officially" is early 15c.; "to send back" is mid-15c.; that of "to turn back" is from c. 1500. Meaning "to give in repayment" is 1590s; that of "give back, restore" c. 1600. Related: Returned; returning.
return (n.)youdaoicibaDictYouDict
late 14c., "act of coming back," also "official report of election results," from Anglo-French retorn, Old French retorne, verbal noun from retorner (see return (v.)). In ball games from 1833; specifically in tennis from 1886. Meaning "a yield, a profit" is recorded from 1620s. Meaning "a thing sent back" is from 1875. Many happy returns of the day was used by Addison (1716). Mailing return address attested from 1884.
returnable (adj.)youdaoicibaDictYouDict
early 15c., from return (v.) + -able.
tapetum (n.)youdaoicibaDictYouDict
of the eye, 1713, from Medieval Latin tapetum, from Latin tapete, collateral form of tapes "carpet, heavy cloth with inwrought figures" (see tapestry).
valetudinarian (n.)youdaoicibaDictYouDict
"one who is constantly concerned with his own ailments," 1703, from valetudinary (1580s), from Latin valetudinarius, from valetudo "state of health" (either good or bad), from valere "be strong" (see valiant) + -tudo, abstract noun suffix (see -tude). Valetudinary (adj.) "sickly" is recorded from 1580s.
inquietudeyoudaoicibaDictYouDict
"Physical or mental restlessness or disturbance", Late Middle English (in the sense 'disturbance of one's quietness or rest'): from Old French, or from late Latin inquietudo, from Latin inquietus, from in- 'not' + quietus 'quiet'.
boletusyoudaoicibaDictYouDict
"A toadstool with pores rather than gills on the underside of the cap, typically having a thick stem", From Latin, from Greek bōlitēs, perhaps from bōlos 'lump'.
detumescenceyoudaoicibaDictYouDict
"The process of subsiding from a state of tension, swelling, or (especially) sexual arousal", Late 17th century: from Latin detumescere, from de- 'down, away'+ tumescere 'to swell'.
papaveretumyoudaoicibaDictYouDict
"A mixture of the hydrochlorides of morphine and other alkaloids in approximately the natural proportions found in opium, used as an analgesic in the treatment of moderate to severe pain and as a preoperative sedative", Early 20th cent. From classical Latin papāver poppy + -etum (in acetum, quinetum, etc.).