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.
Equations vs Functions. When students encounter algebra in high school, the differences between an equation and a function becomes a blur. This is because both use expressions in solving the value for the variable. Then again, the differences between these two are drawn by their outputs. Equations can have one or two values for the variables used depending on the value equated with the expression.