rectilinear
rec.ti.lin.ear \.rek-t*-'lin-e--*r\ aj [LL rectilineus, fr. L rectus + linea line] 1: moving in or forming a straight line 2: characterized by straight lines 3: PERPENDICULAR 4: corrected for distortion so that straight lines are imaged accurately <(~ lens} - rec.ti.lin.ear.ly av