Dictionary.com
Thesaurus.com

bootie

American  
[boo-tee] / ˈbu ti /
Also bootee

noun

  1. a baby's socklike shoe, usually knitted or crocheted, and calf-length or shorter.

  2. a woman's boot having a short leg.

  3. a usually soft, sometimes disposable sock or bootlike covering for the foot or shoe, as for informal wear, warmth, or protection.

    quilted booties for après-ski;

    germfree, throwaway booties for surgical teams.


bootie 1 British  
/ ˈbuːtɪ /

noun

  1. a variant of bootee

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

bootie 2 British  
/ ˈbuːtɪ /

noun

  1. slang a Royal Marine

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of bootie

First recorded in 1790–1800; boot 1 + -ie