Astr. Also in Lat. form pl. luculæ, incorrectly luculi. [a. F. lucule, ad. mod.L. lūcula, dim. of lūx light.] (See quot. 1869.)
1864. Webster, Lucule, a luminous spot on the sun.
1867–77. G. F. Chambers, Astron., I. i. 32. The term luculi has been applied to the constituent specks [on the Sun’s surface].
1869. Phipson, trans. Guillemin’s Sun (1870), 216. Hence those lines of light and shade, luminous and obscure ridges [on the Sun’s disc], which have been called luculæ.
