1. AlgebraIn elementary algebra, a trinomial is a polynomial consisting of three terms or monomials. == Examples of trinomial expressions == 3 x + 5 y + 8 z {\displaystyle 3x+5y+8z} with x , y , z {\displaystyle x,y,z} variables 3 t + 9 s 2 + 3 y 3 {\displaystyle 3t+9s^{2}+3y^{3}} with t , s , y {\displaystyle t,s,y} variables 3 t s + 9 t + 5 s {\displaystyle 3ts+9t+5s} with t , s {\displaystyle... from wikipedia.org