Definition of dray. : a vehicle used to haul goods; especially : a strong cart or wagon without sides.
Expressions versus Equations. A difference between expressions and equations is what each represents. An expression shows a math relationship. One key to an expression is that there is no solution. An expression does not have an answer. An expression, however, can be evaluated. To evaluate an expression, substitute values for the variables.
Key difference: In mathematics, an equation is used to denote the equality between two expressions. An equation and a function are two of the basic foundations of algebra, a subject matter under mathematics. Both can be quite complex in nature, however, in their basic form they may be confused as each other.