- sideline, out of bounds - a line that marks the side boundary of a playing field
--1 is a kind of line
--1 has particulars: touchline - sideline - an auxiliary line of merchandise
--2 is a kind of line, product line, line of products, line of merchandise, business line, line of business
- avocation, by-line, hobby, sideline, spare-time activity - an auxiliary activity
--3 is a kind of pastime, interest, pursuit
--3 has particulars: speleology, spelaeology - avocation, by-line, hobby, sideline, spare-time activity - an auxiliary activity