Other forms: stools
A stool is a simple seat with no back. Three or four legs, and often tall enough for a bar counter.
The missing back is the whole definition, and it is what separates a stool from a chair. English has a bar stool, a piano stool, a milking stool and a step stool for reaching high shelves. There is a completely separate medical sense, since a stool is also a piece of faeces, which is why a doctor may ask for a stool sample. The phrase falling between two stools means failing to get either of two options.
1nounstoolA seat without a back or arms.
“He sat on a stool at the end of the bar.”
A stool is a stand. The Proto-Indo-European word behind it meant a frame or a rack, from the root meaning to stand, so the name is about the legs rather than the seat.
Proto-Indo-European
*steh₂-
Proto-Indo-European
*stoh₂los — frame, rack, stand
Proto-Germanic
*stōlaz — chair
Proto-West Germanic
*stōl
Old English
stōl — chair, seat
Middle English
stool
English, today
stool
Built from
From Middle English stool, from Old English stōl (“chair, seat”), from Proto-West Germanic stōl, from Proto-Germanic stōlaz (“chair”), from Proto-Indo-European stoh₂los (“frame, rack, stand”), from steh₂- (“to stand”). 2 Cognate with frr stuul, stölj, Stööl (“chear”), stq Stoul (“chear”), West Frisian stoel (“chair, seat”), Dutch stoel (“chair”), German Stuhl (“chair”), Low German Stohl (“chair”), lb Stull (“chair”), wym śtül (“chair”), Yiddish שתוהל, שטול (“chair”), Danish, Norwegian Bokmål, Norwegian Nynorsk and Swedish stol (“chair”), Faroese stólur (“chair”), Icelandic stóll (“chair”), gme-cgo stul (“seat”), Gothic 𐍃𐍄𐍉𐌻𐍃 (“chair; throne”), Russian стул (“chair”), Estonian tool (“chair”), Finnish tuoli (“chair”); also Breton and kw sevel (“to erect, rise; to build; to lift; to compose; to earn”), Irish sáil, sál (“heel”), Scottish Gaelic sàil (“heel”), Welsh sefyll (“to stand; to stop; to sit”), Latin sistō (“to set; to stop; to stand; to stabilise”), xum 𐌔𐌄𐌔𐌕𐌖 (“to place”), Greek στέκω, στέκομαι (“to stand up”), Albanian shtoj (“to add; to augment; to accumulate”), Lithuanian stálas (“table”), prg stallan (“table”), be, Bulgarian, mk and Russian стол (“table”), Czech stůl (“table”), Polish stół (“table”), Serbo-Croatian сто̑, сто̑л, stȏ, stȏl (“table”), Slovak stôl (“table”), Slovene stol (“chair”), Armenian երթալ, էթալ (“to go”), ckb ستوون (“column”), ps ستن (“needle; awl; pin; syringe; post; hand; dragonfly”), Persian ایستادن, وایسادن, وایستادن (“to stand up; to step; to stay”), ستون (“column”), kmr rawestîn (“to stand up”), stûn (“column”), os стын (“to stand up”), hit 𒋾𒄑𒍣 (“to step; to place oneself”), xto ṣtäm- (“to stand”), txb stäm- (“to stand”), Sanskrit तिष्ठति (“to stand; to stay”). More at stand.
Etymology from Wiktionary, CC BY-SA