One of 78 in a pack of cards (5)
I believe the answer is:
tarot
'one of 78 in a pack of cards' is the definition.
(Tarot decks have 78 cards each with a tarot)
This is all the clue.
(Other definitions for tarot that I've seen before include "Playing cards" , "Picture card" , "one may have been taken from deck" , "Arcana cards" , "Cards often used in fortune-telling" .)