(1):
(n.) A unit; a single point or spot on a card or die; the card or die so marked; as, the ace of diamonds.
(2):
(n.) Hence: A very small quantity or degree; a particle; an atom; a jot.
(3):
(n.) A single point won by a stroke, as in handball, rackets, etc.; in tennis, frequently, a point won by a service stroke.