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

SECANT is a 6 letter word that starts with S.

1. \Se"cant\, a. [L. secans, -antis, p. pr. of secare to
   cut. See {Section}.]
   Cutting; divivding into two parts; as, a secant line.
   
   

2. \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.
   
   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 line of this line to the radius of the circle.
      See {Trigonometrical function}, under {Function}.