Longman Dictionary of Contemporary English
piano stool
noun
EXAMPLES FROM CORPUS
▪ But Maria was already back up to the piano stool.
Wiktionary
piano stool
n. A round wooden stool used by piano players. It is less stable than the rectangular piano bench. The height can be adjusted by simply spinning the seat clockwise or counterclockwise, respectively.
WordNet
piano stool
n. a stool for piano players; usually adjustable in height [syn: music stool]