noun
legless chair; floor chair
A chair without legs, designed for sitting on tatami flooring; often has a backrest and sometimes armrests.
和室に座椅子を置いて使っている。
I use a legless chair in the Japanese-style room.
座椅子に座ってテレビを見る。
I sit on a floor chair and watch TV.
Compound of 座 (za, 'sitting') and 椅子 (isu, 'chair'). The reading ざいす is a rendaku form of すわる (suwaru, 'to sit') combined with いす.