Definition of "bitsy"

The models are all made to scale — twelve inches for our big new battle wagons and the carriers; the older battleships and the others, cruisers, destroyers, get littler and littler, down to the bitsiest ones.

1994, Josette Dermody Wingo, Mother Was a Gunner's Mate: World War II in the Waves, published 2000, page 25

He never leaves anything out, not the tiniest memo, the bitsiest note.

1995, J.D. Robb (Nora Roberts), Glory in Death, 2000, unnumbered page

“It won′t be making the bitsiest bit of difference, Fielder. […] ”

2001, Eugene Cunningham, Gun Bulldogger‎, page 34