An advertorial is an advertisement that uses the style of newspaper or magazine articles or television documentary programmes, so that it appears to be giving facts and not trying to sell a product.
advertorial in British English
(ˌædvɜːˈtɔːrɪəl)
noun
advertising material presented under the guise of editorial material
Word origin
C20: from advert2 + (edit)orial
advertorial in American English
(ˌædvərˈtɔriəl)
noun
an advertisement, as in a magazine, produced so as to resemble an article or editorial