[f. L. type *tangentia, f. tangent-em TANGENT: see -ENCY.] The quality or condition of being tangent; state of contact.
Problem of tangencies, in old Geom., a problem in which it is required to describe a circle passing through given points, and touching straight lines or circles the position of which is given, the data being limited to three.
1819. Pantologia, s.v., Problem of Tangencies. Ibid. The treatise of tangencies was restored by Vieta.
1832. C. Davies, Treat. Shades & Shadows, 47. The points of tangency are the highest and lowest points of the curve of shade.
1867. F. H. Ludlow, Little Brother, 34. The wildest point of tangency which Man’s railroads make with Weaver’s woods.
1895. H. P. Stokes, in Athenæum, 16 Nov., 690/1. Points of tangency between certain Elizabethan celebrities.
