add. ·- a line pert. or attached to the side of a thing.
2. side line ·add. ·- a secondary road; ·esp., a byroad at right angles to a main road.
3. side line ·add. ·- specif., a line for hobbling an animal by connecting the fore and the hind feet of the same side.
4. side line ·add. ·- a line of goods sold in addition to one's principal articles of trade; a course of business pursued aside from one's regular occupation.