an anatomical structure used as a point of origin in locating other anatomical structures (as in surgery) or as point from which measurements can be taken
a mark showing the boundary of a piece of land
an event marking a unique or important historical change of course or one on which important developments depend; "the agreement was a watershed in the history of both nations"
the position of a prominent or well-known object in a particular landscape; "the church steeple provided a convenient landmark"
(cryogenics) the lowest temperature theoretically attainable (at which the kinetic energy of atoms and molecules is minimal); 0 Kelvin or -273.15 centigrade or -459.67 Fahrenheit
lacking physical depth; having little spatial extension downward or inward from an outer surface or backward or outward from a center; "shallow water"; "a shallow dish"; "a shallow cut"; "a shallow closet"; "established a shallow beachhead"; "hit the ball to shallow left field"
not deep or strong; not affecting one deeply; "shallow breathing"; "a night of shallow fretful sleep"; "in a shallow trance"
lacking depth of intellect or knowledge; concerned only with what is obvious; "shallow people"; "his arguments seemed shallow and tedious"