also: けんだい
noun which may take the genitive case particle 'no'
fist-sized; about the size of a fist
Describes something roughly the size of a human fist. Often used with の to modify a noun.
こぶし大の石を拾った。
I picked up a fist-sized stone.
こぶし大の氷をグラスに入れてください。
Please put a fist-sized piece of ice in the glass.
Kanji spelling; also read けんだい.
Rare on'yomi reading of 拳大.
握りこぶし means a clenched fist, while こぶし大 describes the size of something, not the fist itself.
Compound of こぶし (fist) and 大 (size, large). The reading けんだい is the on'yomi of the kanji 拳大.