Refers to playing cards in general, synonymous with トランプ. The term is a loanword from English 'trump card', but in Japanese it means the whole deck or the cards themselves, not just a trump suit.
from English trump card
See also: トランプ
Please shuffle the playing cards.
He showed me a magic trick with playing cards.
Variant with interpunct, sometimes used for clarity or in older texts.
Loanword from English 'trump card', but the meaning shifted to refer to playing cards in general. The exact path of borrowing is uncertain.