Merriam-Webster's Collegiate® Dictionary, 11th Edition
INCUMBENT
I. noun
Etymology: Middle English, from Anglo-French, from Latin incumbent-, incumbens, present participle of incumbere to lie down on, from in- + -cumbere to lie down; akin to cubare to lie
Date: 15th century
the holder of an office or ecclesiastical benefice, one that occupies a particular position or place,
II. adjective
Date: 1567
imposed as a duty ; obligatory , having the status of an incumbent , lying or resting on something else, bent over so as to rest on or touch an underlying surface