essenceyoudaoicibaDictYouDict[essence 词源字典]
essence: [14] Essence and its derivative essential [14] are the English descendants of the Latin verb ‘to be’, esse (which came ultimately from the Indo-European base *es- ‘be’, source also of English is). From it was formed the abstract noun essentia ‘being, existence’, acquired by English through Old French essence. In the adjective essential, the sense ‘absolutely necessary’ developed via ‘inherent’ and ‘indispensable’ in the 16th century.
=> is[essence etymology, essence origin, 英语词源]
essence (n.)youdaoicibaDictYouDict
late 14c., essencia (respelled late 15c. on French model), from Latin essentia "being, essence," abstract noun formed (to translate Greek ousia "being, essence") from essent-, present participle stem of esse "to be," from PIE *es- "to be" (cognates: Sanskrit asmi, Hittite eimi, Old Church Slavonic jesmi, Lithuanian esmi, Gothic imi, Old English eom "I am;" see be).

Originally "substance of the Trinity;" the general sense of "basic element of anything" is first recorded in English 1650s, though this is the underlying notion of the first English use of essential. Meaning "ingredient which gives something its particular character" is from c. 1600, especially of distilled oils from plants (1650s), hence "fragrance, perfume" (17c.). In 19c. U.S., essence-peddler could mean "medical salesman" and "skunk."