fruityoudaoicibaDictYouDict[fruit 词源字典]
fruit: [12] English acquired fruit via Old French fruit from Latin frūctus, a source more clearly on display in fructify [14], fructose [19], etc. The underlying meaning of the Latin noun seems to have been ‘enjoyment of that which is produced’, for it came, like frūx (source of English frugal), from a base which also produced the verb fruī ‘enjoy’.

By classical times, however, it had passed from ‘enjoyment’ to the ‘product’ itself – the ‘rewards’ of an enterprise, the ‘return’ on an investment, or the ‘produce’ obtained from the soil or from farm animals. When it reached English this latter meaning had narrowed down somewhat, but it was still capable of being used far more broadly, for any ‘edible vegetable’, than we would do today, except in certain archaic expressions such as ‘fruits of the earth’.

The modern restriction to the edible reproductive body of a tree, bush, etc dates from the 13th century. English retains, of course, the more general sense ‘product, result’, although this is now usually expressed by the plural fruits.
=> fructify, frugal[fruit etymology, fruit origin, 英语词源]
fruit (n.)youdaoicibaDictYouDict
late 12c., "any vegetable product useful to humans or animals," from Old French fruit "fruit, fruit eaten as dessert; harvest; virtuous action" (12c.), from Latin fructus "an enjoyment, delight, satisfaction; proceeds, produce, fruit, crops," from frug-, stem of frui "to use, enjoy," from suffixed form of PIE *bhrug- "agricultural produce," also "to enjoy" (see brook (v.)). The Latin word also is the source of Spanish fruto, Italian frutto, German Frucht, Swedish frukt-.

Originally in English meaning all products of the soil (vegetables, nuts, grain, acorns); modern narrower sense is from early 13c. Also "income from agricultural produce, revenue or profits from the soil" (mid-14c.), hence, "profit," the classical sense preserved in fruits of (one's) labor. Meaning "offspring, progeny, child" is from mid-13c.; that of "any consequence, outcome, or result" is from late 14c. Meaning "odd person, eccentric" is from 1910; that of "male homosexual" is from 1935, underworld slang. The term also is noted in 1931 as tramp slang for "a girl or woman willing to oblige," probably from the fact of being "easy picking." Fruit salad recorded from 1861; fruit-cocktail from 1900; fruit-bat by 1869.