jot (n.) Look up jot at
"the least part of anything," 1520s, from Latin iota, from Greek iota "the letter -i-," the smallest letter in the Greek alphabet, also "the least part of anything" (see iota). Usually (and originally) with tittle, from Matthew v.18.
jot (v.) Look up jot at
"to make a short note of, set down quickly in writing or drawing," 1721, apparently from jot (n.) on the notion of a brief note or sketch. Related: Jotted; jotting.