The "corners" or "ends" of the earth are its "wings" (kanephoth ha-'arets), i.e. its borders or extremities. The word in general means a wing, because the wing of a bird is used as a covering for its young, and from this meaning it acquires that of the extremity of anything stretched out. It is thus used in De 22:12: "Thou shalt make thee fringes upon the four borders (wings) of thy vesture, wherewith thou coverest thyself." It thus also means the coasts or boundaries of the land surface of the earth; its extremities. It is translated "corners" in Isa 11:12; "ends" in Job 37:3 and Job 38:13. The "four corners" of the earth (Isa 11:12) or "land" (Eze 7:2) are therefore simply the extremities of the land in the four cardinal directions.
See also ASTRONOMY, sec. III, 3.
E. W. Maunder