Extracts of OED entry for "incumbent, adj."
a. That lies, leans, rests, or presses with its weight upon something else. Const. on.
1624 H. Wotton Archit. in Reliquiæ Wottonianæ (1672) 61 Two Incumbent Figures gracefully leaning upon it towards one another.
1667 Milton Paradise Lost i. 226 With expanded wings he stears his flight Aloft, incumbent on the dusky Air.
1782 T. Pennant Journey Chester to London 88 His figure..is engraven on the incumbent alabaster slab.
1825 ‘J. Nicholson’ Operative Mechanic 96 The wheel, with its incumbent apparatus, weighs about 20 tons.
1853 E. Bulwer-Lytton My Novel II. v. iv. 19 Rising from his incumbent posture.
1853 J. F. W. Herschel Pop. Lect. Sci. (1873) iv. §18. 156 It goes to add to the weight incumbent on the polar.
1781 Gibbon Decline & Fall III. xxx. 161 The nations..must have pressed with incumbent weight on the confines of Germany.
1851 C. Merivale Hist. Romans under Empire III. xxvi. 212 All support was withdrawn, and the incumbent mass of the conquerors rushed headlong over the bodies of their adversaries.
a. Physics. Of air, fluid, or other weight, with reference to the downward pressure exerted by it.
1660 R. Boyle New Exper. Physico-mechanicall ii. 38 The Atmosphere incumbent upon the upper part of the same key or stopple.
1794 G. Adams Lect. Nat. & Exper. Philos. I. i. 17 The lower air presses the palm of the hand as much upwards, as the incumbent column presses the back part downwards.
1831 D. Lardner Pneumatics iii. 243 The elasticity of the air which surrounds us is equal to the weight of the incumbent atmosphere.
b. Geol. Overlying and resting (upon); superimposed, superincumbent, as a stratum.
1789 Mills in Philos. Trans. (Royal Soc.) 80 79 The whole is incumbent on regular basalt pillars, of various dimensions.
1811 J. Pinkerton Petralogy I. 569 Coal sometimes contains..crystals of calcareous spar, perhaps infiltrated from incumbent limestone.
1839 R. I. Murchison Silurian Syst. i. xxxi. 411 The Lower Ludlow shale or mudstone is as uniformly incumbent on the Wenlock limestone.
1874 C. Lyell Elem. Geol. xiii. 190 The shells of the Incumbent yellow sand of the same territory.
c. Bot. Said of an anther when it lies flat against the inner side of the filament; of cotyledons when the back of one is applied to the radicle.
1760 J. Lee Introd. Bot. (1765) ii. xix. 112 The Antheræ incumbent.
1830 J. Lindley Introd. Nat. Syst. Bot. 38 Anthers incumbent, with contiguous lobes.
1851 J. H. Balfour Man. Bot. (ed. 2) §601. 288 The cotyledons are applied to each other by their faces, and the radicle is folded on their back, so as to be dorsal, and the cotyledons are incumbent.
1872 D. Oliver Lessons Elem. Bot. ii. 139 Compare. Sisymbrium, with the radicle curved over the back of one of the cotyledons (incumbent).
d. Entomol. Applied to wings which at rest lie horizontally upon the body, as those of most moths.
1826 W. Kirby & W. Spence Introd. Entomol. IV. 337 Incumbent..wings which when at rest cover the back of the insect.
1856–8 W. Clark tr. J. van der Hoeven Handbk. Zool. I. 321 Wings incumbent.
e. Zool. Of hairs, spines, etc.: Lying along the surface on which they grow.
f. Ornithol. Of the hallux or hind toe of a bird: Resting on the ground or other support with its whole length, its insertion being on a level with the anterior toes ( Cent. Dict.).
a. Resting or falling upon a person as a duty or obligation. Const. on, upon, (also †to).
1567 in J. Row Hist. Kirk Scotl. (Wodrow Soc.) 35 The host of God..shall doe all incumbent to them for the establishing of the true religion.
1637–50 J. Row Hist. Kirk Scotl. (Wodrow Soc.) 344 The first thing incumbent to be done there was to have deposed and excommunicat their Lordships.
1653 O. Cromwell Speech 4 July in Writings & Speeches (1945) III. 56 That there was a duty incumbent upon us.
1713 G. Berkeley Three Dialogues Hylas & Philonous iii. 144 It wou'd still be incumbent on you to shew, those Words were not taken in the vulgar Acceptation.
1851 W. E. Gladstone Gleanings IV. i. 1, I have come home with a deep sense of the duty incumbent upon me.
1865 Reader 14 Jan. 39/1 Our author thinks that it is the incumbent duty of England to promote emigration to such a country.http://www.oed.com/view/Entry/94133?rskey=1Z9...