jot

Concise Bible Dictionary:

This refers to the Hebrew letter yod, the smallest letter in the language (Matt. 5:1818For verily I say unto you, Till heaven and earth pass, one jot or one tittle shall in no wise pass from the law, till all be fulfilled. (Matthew 5:18)). The word used is iota, which is the Greek equivalent for the same letter.

Strong’s Dictionary of Greek Words:

Greek:
ἰῶτα
Transliteration:
iota
Phonic:
ee-o’-tah
Meaning:
of Hebrew origin (the tenth letter of the Hebrew alphabet); "iota", the name of the eighth letter of the Greek alphabet, put (figuratively) for a very small part of anything
KJV Usage:
jot