骨牌
こ
っ
ぱ
い
Meanings
1
General term for playing cards, including Western-style cards. Less common than トランプ in modern Japanese.
It's been a while since I played with playing cards.
2
mahjong tiles made of animal bone
Specifically refers to mahjong tiles crafted from animal bone, as opposed to modern plastic or other materials. Domain-specific term used in mahjong contexts.
These mahjong tiles are made of cow bone, not ivory.