(1):
(n.) An event which may or may not happen; that which is unforeseen, undetermined, or dependent on something future; a contingency.
(2):
(n.) That which falls to one in a division or apportionment among a number; a suitable share; proportion; esp., a quota of troops.
(3):
(a.) Possible, or liable, but not certain, to occur; incidental; casual.
(4):
(a.) Dependent on that which is undetermined or unknown; as, the success of his undertaking is contingent upon events which he can not control.
(5):
(a.) Dependent for effect on something that may or may not occur; as, a contingent estate.