Internet business (6)
I believe the answer is:
dotcom
'internet business' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for dotcom that I've seen before include "Suffix often attached to website address (3.3)" , "Company that conducts its business on the Internet" , "Internet company (colloq.)" , "Internet address suffix" , "On-line business" .)