[The same as] instantly, [i.e. used as] an adverb;[1] [meaning] in a short time, in a moment.
But Aristophanes in Wealth [sc. uses the phrase] "in an instant": "I was thrown down out of doors naked in an instant." [Meaning] in the merest [hair's breadth], that which cannot be cut through or cropped through shortage of time. It has been derived from the small hairs, the ones which because of shortness cannot be cut [karh=nai]. There is a [related] adverb a)karw=s ["instantly"]. From which [comes] the adverbial word a)kare/s.[2]
But [note also] kari/, [in the phrase?] tw=| kari/, [which declines] ka/r, karo/s, kari/.[3]