bootee

Etymology

From boot + -ee (diminutive suffix).

noun

1. A soft, woolen shoe, usually knitted, for a baby or small pet.
   Take off the baby's bootees before you put her in the crib.
   ‘No,’ said Luke, grinning at her. ‘You're not dull enough! […] What about the kid's clothes? I don't suppose they were anything to write home about, but didn't you keep anything? A bootee or a bit of embroidery or anything at all?’ 1963, Margery Allingham, chapter 15, in The China Governess
2. A thick sock worn under a wetsuit.
3. An overshoe or sock worn to cover dirty shoes or feet.
   Surgeons often slip on bootees before entering the operating room.
   Coordinate term: slipper