Tot
early 18th century (originally dialect): of unknown origin.
wiktionary
Borrowed from Scots tot, a shortened form of totum(“small child; tot”), of uncertain origin. Compare totter, tottle. Compare also Old Norse tottr(“name of a dwarf”), Swedish tutte(“small child”), Danish tommeltot(“little child”).
Short for total(“to sum”).
etymonline
tot (n.)
"little child," 1725, Scottish, of uncertain origin, perhaps a shortened form of totter, or related to Old Norse tottr, nickname of a dwarf (compare Swedish tutte "little child," Danish tommel-tot "little child," in which the first element means "thumb"). Tot-lot "play ground for young children" is recorded from 1944.
tot (v.)
"to reckon up," 1760, from tot (n.) "total of an addition," first recorded 1680s, short for total (n.). Hence, "to mark (an account or a name) with the word 'tot.'"
