a. [f. LACUNA + -ARY2; after F. lacunaire.]
1. Of or pertaining to a lacuna; consisting of or resembling lacunæ.
1857. E. C. Otté, trans. Quatrefages’ Rambles Nat., II. 289. Lacunary passages connected these two cavities together.
1868. P. M. Duncan, Insect World, Introd. 14. On reaching the interior of the head it opens in the lacunary interorganic system.
2. Math. Lacunary function (see quots.). Lacunary space: an area in a plane, every point of which is the affix of a value of the variable for which a given function has no determinate values.
1893. Cayley, in Q. Jrnl. Math., May, 281. A function such as this, existing only for points within a certain region and not for the whole of the infinite plane, is said to be a lacunary function.
1893. A. R. Forsyth, Theory Functions, § 87. 141. Weierstrass was the first to draw attention to lacunary functions as they may be called. Ibid., 143. The first step in the construction of a function which shall have any assigned lacunary space.
