Definition of "cline"

This account effectively reconstructs the well-known grammaticalisation cline from anaphora to agreement, …

2005, Ronnie Cann, Ruth Kempson, Lutz Marten, The Dynamics of Language, an Introduction, page 412

Let C1 and C2 be two nonintersecting clines. Prove that there is a unique pair of points that are simultaneously symmetric to both C1 and C2.

2001, Michael Henle, Modern Geometries: Non-Euclidean, Projective, and Discrete‎, page 77

To visualize Möbius transformations, it is helpful to focus on fixed points and, in the case of two fixed points, on two families of clines with respect to these points.

2009, Michael P. Hitchman, Geometry with an Introduction to Cosmic Topology‎, page 64

Let Ω be a fixed, arbitrary, point. Then circles (in the classical sense) through Ω can be considered as lines. For convenience, such circles are called clines in this section. Two distinct clines cut in one point (ignoring Ω and the two cyclic points); it can happen that Ω is a double intersection point; in this case, one may say that the two clines are parallel, and that they meet at a point at infinity, which is Ω.

2011, Dominique Michelucci, What is a Line?, Pascal Schreck, Julien Narboux, Jürgen Richter-Gebert (editors), Automated Deduction in Geometry, 8th International Workshop, ADG 2010, Revised Selected Papers, LNAI 6877, page 139