Merriam-Webster's Collegiate® Dictionary, 11th Edition
STOOL
I. noun
Etymology: Middle English, from Old English stōl; akin to Old High German stuol chair, Old Church Slavic stolŭ seat, throne Date: before 12th century
1. a seat usually without back or arms supported by three or four legs or by a central pedestal, a low bench or portable support for the feet or knees ; footstool , a seat used as a symbol of office or authority,
3. a seat used while defecating or urinating, a discharge of fecal matter,
4. a stump or group of stumps of a tree especially when producing suckers, a plant crown from which shoots grow out, a shoot or growth from a stool, stool pigeon 1,
II. intransitive verb
Date: 1770
to throw out shoots in the manner of a stool