(1):
(n.) That which is physically incumbent; that which lies as a burden; a weight.
(2):
(n.) The state of being incumbent; a lying or resting on something.
(3):
(n.) That which is morally incumbent, or is imposed, as a rule, a duty, obligation, or responsibility.
(4):
(n.) The state of holding a benefice; the full possession and exercise of any office.