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"
any of the more than 100 known substances (of which 92 occur naturally) that cannot be separated into simpler substances and that singly or in combination constitute all matter
having existed from the beginning; in an earliest or original stage or state; "aboriginal forests"; "primal eras before the appearance of life on earth"; "the forest primeval"; "primordial matter"; "primordial forms of life"
of or pertaining to members of the indigenous people of Australia; "an Aboriginal rite"
the musical interval between one note and another three notes away from it; "a simple harmony written in major thirds"
following the second position in an ordering or series; "a distant third"; "he answered the first question willingly, the second reluctantly, and the third with resentment"
coming next after the second and just before the fourth in position
in the third place; "third we must consider unemployment"