Etymology Borrowed from Scots tot, a shortened form of totum (“small child; tot”), of uncertain origin, perhaps shortened from totter (“to move in an unsteady way”), Compare tottle, also Old Norse tottr (“name of a dwarf”), Swedish tutte (“small child”), Danish tommeltot (“little child”).
1
A small child.
He learned to run when he was just a tot.
When I was but a tiny tot, I knocked the neighbors cold / For I became to walk when I was scarcely one year old1907, Dave Reed Jr, “You'll Have to Get Off and Walk: Comic Novelty Song and Refrain”, M. Witmark & Sons:
1 more example
Death conditioning begins at eighteen months. Every tot spends two mornings a week in a Hospital for the Dying. All the best toys are kept there, and they get chocolate cream on death days.1932, Aldous Huxley, Brave New World, London: Chatto & Windus:
2
A small amount of liquor, (particularly) a small measure of rum.
Then I give them a tot of rum apiece, as they sit huddled in their blankets.1897, Mary H. Kingsley, Travels in West Africa:
And tot of rum to send him warm to sleep.1916, Siegfried Sassoon, The Working Party:
There are, of course, many ways to proceed from here, the most likely being that you, as an experienced tradesman, would simply know what these amounts come to (in terms of groups of ten) and can tot them up in your head.2017, Paul Lockhart, Arithmetic:
2
UK, Historical To mark (a debt) with the word tot (Latin for "so much"), indicating that it was good or collectible for the amount specified.