Stories We Like: A Guide to the Comma
Old English rædere "person who reads aloud to others; lector; scholar; diviner, interpreter," agent noun from rædan (see read (v.)). Cf. Dutch rader "adviser," Old High German ratari "counselor." Old English fem. form was rædistre.
Marked playing cards: The cards and dice were crooked, the cards being readers (1894+ Gambling)