an imaginary line around the Earth forming the great circle that is equidistant from the north and south poles; "the equator is the boundary between the northern and southern hemispheres"
a circle dividing a sphere or other surface into two usually equal and symmetrical parts
not tried or tested by experience; "unseasoned artillery volunteers"; "still untested in battle"; "an illustrator untried in mural painting"; "a young hand at plowing"
one of the quantities in a mathematical proportion
properly related in size or degree or other measurable characteristics; usually followed by `to'; "the punishment ought to be proportional to the crime"; "earnings relative to production"