Microsite

Microsite is a limited area on the Web managed and paid for by an external advertiser/company.

Definition

According to Marketing Management by Keller and Kotler (15th edition),

Microsite. A limited area on the Web managed and paid for by an external advertiser/company.

According to the Marketing Communications by Fill (5th edition),

Microsite. A small web site or a part of a web site that has a separate URL to its home page, but the content is related. Often used as a temporary web site to promote a new product or event.