The Collaborative International Dictionary of English v.0.48:

Secant \Se"cant\ (s[=e]"k[a^]nt), a. [L. secans, -antis, p. pr.
   of secare to cut. See Section.]
   Cutting; dividing into two parts; as, a secant line.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Secant \Secant\, n. [Cf. F. s['e]cante. See Secant, a.]
   1. (Geom.) A line that cuts another; especially, a straight
      line cutting a curve in two or more points.
      [1913 Webster]

   2. (Trig.) A right line drawn from the center of a circle
      through one end of a circular arc, and terminated by a
      tangent drawn from the other end; the number expressing
      the ratio of this line to the radius of the circle. See
      Trigonometrical function, under Function.
      [1913 Webster]

WordNet (r) 3.0 (2006):

secant
    n 1: a straight line that intersects a curve at two or more
         points
    2: ratio of the hypotenuse to the adjacent side of a right-
       angled triangle [syn: secant, sec]

Moby Thesaurus II by Grady Ward, 1.0:

40 Moby Thesaurus words for "secant":
   air line, axis, beeline, chiasmal, chiasmic, chiastic, chord,
   crisscross, cross, crosscut, crossed, crossing, cut across,
   decussate, decussated, diagonal, diameter, direct line, directrix,
   edge, great-circle course, intersected, intersecting, normal,
   perpendicular, radius, radius vector, right line, segment,
   shortcut, side, straight, straight course, straight line,
   straight stretch, straightaway, streamline, tangent, transversal,
   vector