lunule
(ˈl(j)uːnjʊl)
[a. F. lunule, ad. L. lūnula, dim. of lūna moon.]
1. Nat. Hist. A crescent-shaped mark, spot, etc.
| 1828 Stark Elem. Nat. Hist. I. 138 Whitish lunules on the tail-feathers. 1845 Westwood Brit. Moths II. 14 With two rather slightly marked strigæ (between which is a white lunule). |
2. Geom. = lune3 1. (Cf. lunula 1 a.)
| 1737 in Bailey vol. II. 1817 Colebrooke Algebra, etc. 96 A lunule or meniscus. 1872 De Morgan Budget of Paradoxes 45 This [Porta's Elementa Curvilineorum] is a ridiculous attempt, which defies description, except that it is all about lunules. |
3. Conch. The crescent-shaped depression in front of the umbo. (Cf. lunula 4 a.)
| 1842 Sowerby Conch. Man. (ed. 2) 179. 1851–6 Woodward Mollusca 298 Cyprina,..umbones oblique; no lunule. 1863 J. G. Jeffreys Brit. Conchol. II. 233 Lunule deep and heart⁓shaped. 1866 Tate Brit. Mollusks ii. |
Hence ˈlunuled a., crescent-shaped.
| 1863 Reeve Land & Freshwater Mollusks 236 Shell large, oval-globose, slightly lunuled. |