(1):

(v. i.) To give or use one's power or influence for any object; to assist.

(2):

(v. i.) To give a part to a common stock; to lend assistance or aid, or give something, to a common purpose; to have a share in any act or effect.

(3):

(v. t.) To give or grant i common with others; to give to a common stock or for a common purpose; to furnish or suply in part; to give (money or other aid) for a specified object; as, to contribute food or fuel for the poor.