-used to combine tuples from two relations in a combinatorial fashion.
-Denoted by R(A1, A2, . . ., An) x S(B1, B2, . . ., Bm)
-Result is a relation Q with degree n + m attributes:
Q(A1, A2, . . ., An, B1, B2, . . ., Bm), in that order.
-The resulting relation state has one tuple for each combination of tuples—one from R and one from S.
-Hence, if R has nR tuples (denoted as |R| = nR ), and S has nS tuples, then R x S will have nR * nS tuples.
-The two operands do NOT have to be "type compatible"