1. The condition or quality of being equal; agreement in quantity or degree as compared; likeness in bulk, value, rank, properties, etc.; as, the equality of two bodies in length or thickness; an equality of rights.
4. (Science: mathematics) Exact agreement between two expressions or magnitudes with respect to quantity; denoted by the symbol =; thus, a = x signifies that a contains the same number and kind of units of measure that x does.