coition

from WordNet (r) 3.0 (2006)

coition
    n 1: the act of sexual procreation between a man and a woman;
         the man's penis is inserted into the woman's vagina and
         excited until orgasm and ejaculation occur [syn: {sexual
         intercourse}, {intercourse}, {sex act}, {copulation},
         {coitus}, {coition}, {sexual congress}, {congress}, {sexual
         relation}, {relation}, {carnal knowledge}]

from The Collaborative International Dictionary of English v.0.48

Coition \Co*i"tion\, n. [L. coitio, fr. coire to come together;
   co- + ire to go.]
   A coming together; sexual intercourse; copulation. --Grew.
   [1913 Webster]