late 14c., poesie, "poetry; poetic language and ideas; literature; a poem, a passage of poetry," from Old French poesie (mid-14c.), from Vulgar Latin *poesia (source of Provençal, Spanish, Portuguese, Italian poesia), from Latin poesis "poetry, a poem," from Greek poēsis "composition, poetry," literally "a making, fabrication," variant of poiēsis, from poein, poiein "to make or compose" (see poet). Meaning "the art of poetic composition, skill in making poems" is from late 15c.

A poem, as I have told you, is the work of the poet; the end and fruit of his labour and study. Poesy is his skill or craft of making; the very fiction itself, the reason or form of the work. [Ben Jonson, "Discoveries"]

"the act of working together to one end," 1620s, from French coopération, or directly from Late Latin cooperationem (nominative cooperatio) "a working together," noun of action from past-participle stem of cooperari "to work together," from assimilated form of com "with, together" (see com-) + operari "to work," from PIE root *op- "to work, produce in abundance."