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.
The main difference between an equation and a function is the fact that an equation usually deals with a single input, whereas, a function can have numerous inputs. In mathematics, an equation is used to denote the equality between two expressions.