

Math.com Trig Overview (Site not responding. Last check: ) 
  Under its simplest definition, a trigonometric (literally, a "trianglemeasuring") function, is one of the many functions that relate one nonright angle of a right triangle to the ratio of the lengths of any two sides of the triangle (or vice versa). 
  Furthermore, the functions are usually abbreviated: sine (sin), cosine (cos), tangent (tan) cosecant (csc), secant (sec), and cotangent (cot). 
  Therefore, the tangent function is the same as the quotient of the sine and cosine functions (the tangent function is still fairly handy). 
 www.math.com /tables/algebra/functions/trig/overview.htm (886 words) 
