CHECK n. 2 definitions
A mark, certificate, or token, by which, errors may be prevented, or a thing or person may be identified; as, checks placed against items in an account; a check given for baggage; a return check on a railroad.
CHECKER v.
To variegate or diversify with different qualities, color, scenes, or events; esp., to subject to frequent alternations of prosterity and adversity. Our minds are, as it were, checkered with truth and falsehood. Addison.