[a. F. concavité (14th c.), ad. L. concavitās: see CONCAVE and -ITY.]
1. The quality or condition of being concave; hollowness.
1578. Lyte, Dodoens, I. xxv. 37. The leafe … is rounde and thicke … With some hollownes or concauitie above.
1605. Camden, Rem. (1657), 351. A glass of parabolical concavitie, or burning glass, as some call it.
1794. G. Adams, Nat. & Exp. Philos., II. xv. 187. If the radius of concavity be less than the radius of convexity.
1840. Carlyle, Heroes (1858), 263. No twisted, poor convex-concave mirror, reflecting all objects with its own convexities and concavities.
1865. Geikie, Scen. & Geol. Scot., vi. 121. The profound concavity of these valleys.
2. A concave surface or side, a hollow vault; each of the hollow ‘spheres’ of ancient astronomy.
1483. Caxton, Gold. Leg., 24/2 (R. Supp.). Fro the centre of therthe vnto the concavite of the heuen of Saturne.
1549. Compl. Scot., vi. (1872), 47. The regione celest vitht in the concauite of the quhilk is closit the regione elementar.
1561. Eden, Arte Nauig., I. v. 7. The water and earth … are conteyned vnder the concauitie of the ayre.
1603. Drayton, Bar. Wars, VI. xxxi. An Hemisphere; In whose Concavitie, she did compose The Constellations.
1703. Moxon, Mech. Exerc., 220. An Hollow-Mandrel, made fit stifly to receive the convexity of the Globe in its concavity.
1868. Lockyer, Guillemin’s Heavens (ed. 3), 277. An orbit the concavity of which is always turned towards the Sun.
3. A hollow; a cavity.
1513. Bradshaw, St. Werburge, I. 2810. Of the sayd oke tree is a famous opynyon That no man may entre the sayd concauyte In deedly synne bounden.
1578. Banister, Hist. Man, I. 3. These concauities are also encreased by the Gristles in some of them growing.
1634. R. H., Salernes Regim., 155. In the concavities of the Teeth.
a. 1652. Brome, Queene’s Exch., V. Wks. 1873, III. 536. Concavities … for Rich men to hide their treasure in.
1848. J. A. Carlyle, trans. Dante’s Inferno, VII. We descended into the fourth concavity.
† b. The bore of a gun. Obs. Cf. CONCAVE sb. 1 b.
1669. Sturmy, Mariner’s Mag., V. 79. How a Shot which sticketh fast within the Concavity of a Piece … may be Shot out.
† 4. fig. A recondite matter; a profundity.
1650. Ashmole, Chym. Collect., 27. Bringing confusion and discouragement to the young learner, troubling his mind with so many obseruations and seuerall concauities.
1658. Ussher, Ann., 191. The more inquisitive and diligent in searching out and describing the concavities of them.
