Paid-for content which is designed to have the same appearance as an editorial piece to give the impression that it is part of the editorial content rather than an advert. Readers will be able to identify the piece as ‘promotional’ or as ‘advertorial’. Major advertisers deliberately style their placements to appear as the editorial (non-advertisement) content of a newspaper or magazine.

See also:
Advertising Cost Equivalent (ACE)
Advertising
Editorial
Above the line
Below the line