1.  line of business(n = noun.artifact) business line, line, line of merchandise, line of products, product line - a particular kind of product or merchandise; "a nice line of shoes"
is a kind of merchandise, product, ware
has parts: top of the line
has particulars: sideline

2.  line of business(n = noun.act) field, field of operation - a particular kind of commercial enterprise; "they are outstanding in their field"
is a kind of business, business enterprise, commercial enterprise

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