back side
131side — 1 /saId/ noun (C) PLACE/AREA/POSITION 1 PART OF AN AREA one of the two areas that are on either the left or the right of an imaginary line, or on either the left or the right of a border, wall, river etc: Drive on the left hand side of the road.… …
132back pressure — [1] The resistance to the flow of exhaust gases through the exhaust system. By rerouting the exhaust gases for noise suppression, a muffler causes back pressure, but a straight pipe alone causes only minimal back pressure. Some engines require… …
