amphibiousyoudaoicibaDictYouDict[amphibious 词源字典]
amphibious: [17] The Greek prefix amphimeant ‘both, on both sides’ (hence an amphitheatre [14]: Greek and Roman theatres were semicircular, so two joined together, completely surrounding the arena, formed an amphitheatre). Combination with bios ‘life’ (as in biology) produced the Greek adjective amphibios, literally ‘leading a double life’. From the beginning of its career as an English word it was used in a very wide, general sense of ‘combining two completely distinct or opposite conditions or qualities’ (Joseph Addison, for example, used it as an 18th-century equivalent of modern unisex), but that meaning has now almost entirely given way to the word’s zoological application.

At first, amphibious meant broadly ‘living on both land and water’, and so was applied by some scientists to, for example, seals; but around 1819 the zoologist William Macleay proposed the more precise application, since generally accepted, to frogs, newts, and other members of the class Amphibia whose larvae have gills but whose adults breathe with lungs.

=> biology[amphibious etymology, amphibious origin, 英语词源]
Anabaptist (n.)youdaoicibaDictYouDict
1530s, "one who baptizes over again," from Modern Latin anabaptista, from Latin anabaptismus "second baptism" (used in literal sense from 4c.; see anabaptism).

Originally in English in reference to sect that practiced adult baptism and arose in Germany 1521. Probably so called because, as a new faith, they baptized converts who already had been baptized (as infants) in the older Christian churches. Modern branches only baptize once (adults) and do not actively seek converts. The name also was applied, usually opprobriously, to Baptists, perhaps due to the multiple immersions of their baptisms.
cholera (n.)youdaoicibaDictYouDict
late 14c., "bile, melancholy" (originally the same as choler), from Middle French cholera or directly from Late Latin cholera, from Greek kholera "a type of disease characterized by diarrhea, supposedly caused by choler" (Celsus), from khole "gall, bile," from khloazein "to be green," from khloros (see Chloe). But another sense of khole was "drainpipe, gutter."

Revived 1560s in classical sense as a name for a severe digestive disorder (rarely fatal to adults); and 1704 (especially as cholera morbus), for a highly lethal disease endemic in India, periodically breaking out in global epidemics, especially that reaching Britain and America in the early 1830s.
gum (v.2)youdaoicibaDictYouDict
of infants, toothless adults, etc., "to chew or gnaw (something) with the gums," by 1907, from gum (n.2). Related: Gummed; gumming.
pig (n.)youdaoicibaDictYouDict
probably from Old English *picg, found in compounds, ultimate origin unknown. Originally "young pig" (the word for adults was swine). Apparently related to Low German bigge, Dutch big ("but the phonology is difficult" -- OED). The meaning "oblong piece of metal" is first attested 1580s, on the notion of "large mass." Applied to persons, usually in contempt, since 1540s; the derogatory slang meaning "police officer" has been in underworld slang since at least 1811.
The pigs frisked my panney, and nailed my screws; the officers searched my house, and seized my picklock keys. ["Dictionary of Buckish Slang, University Wit and Pickpocket Eloquence," London, 1811]
Another Old English word for "pig" was fearh, related to furh "furrow," from PIE *perk- "dig, furrow" (source also of Latin porc-us "pig," see pork). "This reflects a widespread IE tendency to name animals from typical attributes or activities" [Lass]. Synonyms grunter, porker are from sailors' and fishermen's euphemistic avoidance of uttering the word pig at sea, a superstition perhaps based on the fate of the Gadarene swine, who drowned. The image of a pig in a poke is attested from 1520s (see poke (n.3)). Flying pigs as a type of something unreal is from 1610s.
stork (n.)youdaoicibaDictYouDict
Old English storc "stork," from Proto-Germanic *sturkaz (cognates: Old Norse storkr, Swedish and Danish stork, Middle Dutch storc, Old High German storah, German Storch "stork"), from PIE *ster- "stiff" (cognates: Old English stear "stiff, strong;" see stark). Perhaps so called with reference to the bird's stiff or rigid posture. But some connect the word to Greek torgos "vulture."

Old Church Slavonic struku, Russian sterkhu, Lithuanian starkus, Hungarian eszterag, Albanian sterkjok "stork" are said to be Germanic loan-words. The children's fable that babies are brought by storks (told by adults who aren't ready to go into the details) is in English by 1854, from German and Dutch nursery stories, no doubt from the notion that storks nesting on one's roof meant good luck, often in the form of family happiness.
XyoudaoicibaDictYouDict
The entire entry for X in Johnson's dictionary (1756) is: "X is a letter, which, though found in Saxon words, begins no word in the English language." Most English words beginning in -x- are of Greek origin or modern commercial coinages. East Anglian in 14c. showed a tendency to use -x- for initial sh-, sch- (such as xal for shall), which didn't catch on but seems an improvement over the current system. As a symbol of a kiss on a letter, etc., it is recorded from 1765. In malt liquor, XX denoted "double quality" and XXX "strongest quality" (1827).

Algebraic meaning "unknown quantity" (1660 in English, from French), sometimes is said to be from medieval use, originally a crossed -r-, in that case probably from Latin radix (see root (n.)). Other theories trace it to Arabic (Klein), but a more prosaic explanation says Descartes (1637) took x, y, z, the last three letters of the alphabet, for unknowns to correspond to a, b, c, used for known quantities.

Used allusively for "unknown person" from 1797, "something unknown" since 1859. As a type of chromosome, attested from 1902 (first so called in German; Henking, 1891). To designate "films deemed suitable for adults only," first used 1950 in Britain; adopted in U.S. Nov. 1, 1968. The XYZ Affair in American history (1797) involved French agents designated by those letters.
creatinuriayoudaoicibaDictYouDict
"The presence of creatine in the urine, normal in children but usually associated with muscle disease or muscle breakdown in adults", Early 20th cent.; earliest use found in The Lancet. From creatine + -uria.