[L. lūnula, dim. of lūna moon.]
1. a. Geom. = LUNE3 1, LUNULE 2. † b. (See quot. 1712), Obs.
1571. Digges, Pantom., II. xiv. O j. Ye last figure called a Lunula. Ibid. (1579), Stratiot., 104. All others as the Lunula … and Hexagonall Battailes.
1700. Wallis, in Phil. Trans., XXI. 411. The Squaring a certain Lunula by Hippocrates Chius long since, hath been known … for many Ages.
1712. Desaguliers, trans. Ozanam’s Mech., 123. We call Lunula a Plain terminated by the Circumferences of Two Circles, which touch one another on the inside [etc.].
1881. Routledge, Science, ii. 37. The areas of the lunulae AFBD,BGCE.
† 2. A satellite. rare–1. Obs. (Cf. F. lunule.)
1676. Glanvill, Ess., iii. 18. The Ansulæ Saturni, the Asseclæ of Jupiter … By these Lunulæ ’tis thought that Jupiters distance from the Earth may be determined.
3. a. Nat. Hist. A crescent-shaped mark = LUNULE 1. b. The white crescent-shaped mark at the base of the finger-nails.
1828. Quain, Elem. Anat., 699. At the posterior, or attached extremity [of the nail], a small portion will be observed differing in colour from the rest, and usually called lunula, from its form.
1874. Coues, Birds N. W., 703. The frontal lunula reaches but little beyond the eyes, instead of nearly half an inch behind them.
1891. Brit. Med. Jrnl., 12 Sept., 624/2. A patient … who had a lunula on each thumbnail only.
1897. Allbutt’s Syst. Med., II. 361. A white band and a furrow at the lunula of the nails.
4. a. Conch. = LUNULE 3. b. Anat. (See quot.)
1835–6. Todd, Cycl. Anat., I. 711/2. The lunula does not occur in every genus of bivalve shell.
1856. Quain’s Anat. (ed. 6), III. 240. [In the heart] two narrow lunated portions, one on each side of the nodule and adjoining the free margin of the valve. These parts … are named lunulæ.
1875. T. Hayden, Dis. Heart, 24. This is the lunula.
