Or Iota, the smallest letter of the Greek alphabet, used metaphorically or proverbially for the smallest thing (Matt. 5:18); or it may be = yod, which is the smallest of the Hebrew letters.

the English form of the Greek iota, i.e., the smallest letter of the Greek alphabet. The Hebrew is yod, or y formed like a comma (’). It is used metaphorically to express the minutest thing.