Without looking at the dictionary, I think the origin of the word “thousands” is when someone said, “Thou give me as many cookies as there are grains of sand.” Eventually it got shortened down to thousands.
Where the word “THOUSANDS” originated
Happening right now on Spudart: Press a leaf in an envelope with the date and story written on it until 2026-10-31

This has also been tweeted at http://twitter.com/spudart/status/3127847806
The Online Etymology Dictionary essentially has no idea what the origin of “thousand” is. I mean really. Just look ath their definition. http://www.etymonline.com/index.php?search=thousand&searchmode=none They totally just jarble all over the place.
I like saying “Those-a N.D.S.”