line - in games or sports; a mark indicating positions or bounds of the playing area

touchline - either of the sidelines in soccer or Rugby

line of business, line of merchandise, line of products, product line, business line, line - a particular kind of product or merchandise; "a nice line of shoes"

pastime, pursuit, interest - a diversion that occupies one's time and thoughts (usually pleasantly); "sailing is her favorite pastime"; "his main pastime is gambling"; "he counts reading among his interests"; "they criticized the boy for his limited pursuits"

spelaeology, speleology - the pastime of exploring caves