(a.) Lying, resting, or imposed, as a duty or obligation; obligatory; always with on or upon.
(4):
(a.) Leaning or resting; -- said of anthers when lying on the inner side of the filament, or of cotyledons when the radicle lies against the back of one of them.
(5):
(a.) Bent downwards so that the ends touch, or rest on, something else; as, the incumbent toe of a bird.