\Side line\
1.
   (a) A line pert. or attached to the side of a thing.
   (b) Specif., a line for hobbling an animal by connecting
       the fore and the hind feet of the same side.
2.
   (a) 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.
   (b) A secondary road; esp., a byroad at right angles to a
       main road. [Canada]