a : something just like a rock in firmness: (1) : foundation, help The superintendent describes [Michael] Doran as a rock on which the achievements of The varsity is and can go on being developed.—?? ???? ??? ??? ??? ????????? ?? ???? ???? ???? ?????? ?? ????? ?? ????? ????? ???? ???? ???? ???? ????. Thomas Youthful's sketch of a double-slit exp