meat (n.)youdaoicibaDictYouDict
Old English mete "food, item of food" (paired with drink), from Proto-Germanic *mati (cognates: Old Frisian mete, Old Saxon meti, Old Norse matr, Old High German maz, Gothic mats "food," Middle Dutch, Dutch metworst, German Mettwurst "type of sausage"), from PIE *mad-i-, from root *mad- "moist, wet," also with reference to food qualities, (cognates: Sanskrit medas- "fat" (n.), Old Irish mat "pig;" see mast (n.2)).

Narrower sense of "flesh used as food" is first attested c. 1300; similar sense evolution in French viande "meat," originally "food." In Middle English, vegetables still could be called grene-mete (15c.). Figurative sense of "essential part" is from 1901. Dark meat, white meat popularized 19c., supposedly as euphemisms for leg and breast, but earliest sources use both terms without apparent embarrassment.
The choicest parts of a turkey are the side bones, the breast, and the thigh bones. The breast and wings are called light meat; the thigh-bones and side-bones dark meat. When a person declines expressing a preference, it is polite to help to both kinds. [Lydia Maria Child, "The American Frugal Housewife," Boston, 1835]
First record of meat loaf is from 1876. Meat-market "place where one looks for sex partners" is from 1896 (meat in various sexual senses of "penis, vagina, body regarded as a sex object, prostitute" are attested from 1590s; Old English for "meat-market" was flæsccyping ('flesh-cheaping')); meat wagon "ambulance" is from 1920, American English slang, said to date from World War I (in a literal sense by 1857). Meat-grinder in the figurative sense attested by 1951. Meat-hook in colloquial transferred sense "arm" attested by 1919.
pith (n.)youdaoicibaDictYouDict
Old English piþa "pith of plants," also "essential part," from West Germanic *pithan- (cognates: Middle Dutch pitte, Dutch pit, East Frisian pit), a Low German root of uncertain origin. Figurative sense was in Old English. Pith helmet (1889, earlier pith hat, 1884) so called because it is made from the dried pith of the Bengal spongewood.
substance (n.)youdaoicibaDictYouDict
c. 1300, "essential nature, real or essential part," from Old French sustance, substance "goods, possessions; nature, composition" (12c.), from Latin substantia "being, essence, material," from substans, present participle of substare "stand firm, stand or be under, be present," from sub "up to, under" (see sub-) + stare "to stand," from PIE root *sta- "to stand" (see stet). Latin substantia translates Greek ousia "that which is one's own, one's substance or property; the being, essence, or nature of anything." Meaning "any kind of corporeal matter" is first attested mid-14c. Sense of "the matter of a study, discourse, etc." first recorded late 14c.
substantial (adj.)youdaoicibaDictYouDict
mid-14c., "ample, sizeable," from Old French substantiel (13c.) and directly from Latin substantialis "having substance or reality, material," in Late Latin "pertaining to the substance or essence," from substantia "being, essence, material"(see substance). Meaning "existing, having real existence" is from late 14c. Meaning "involving an essential part or point" is early 15c. Related: Substantially.
wing (v.)youdaoicibaDictYouDict
c. 1600, "take flight;" 1610s, "fit with wings," from wing (n.). Meaning "shoot a bird in the wing" is from 1802, with figurative extensions to wounds suffered in non-essential parts. Verbal phrase wing it (1885) is said to be from a theatrical slang sense of an actor learning his lines in the wings before going onstage, or else not learning them at all and being fed by a prompter in the wings; but perhaps it is simply an image of a baby bird taking flight from the nest for the first time (the phrase is attested in this sense from 1875). Related: Winged; winging.
idiochromaticyoudaoicibaDictYouDict
"Of a mineral: deriving its colour or optical properties from the chemicals which are an essential part of its composition", Mid 19th cent.; earliest use found in James Nicol (1810–1879), geologist. From idio- + chromatic, after German idiochromatisch.