Ask.com, which is owned by IAC, said that the Lexico acquisition will grow the Ask Network user base to more than 145m unique users worldwide. This would rank it as the 9th largest web property, ahead of Apple and Facebook, according to comScore World Metrix.
Jim Safka, CEO of Ask.com, said: "More than 30% of all searches conducted on Ask.com are in the reference category. In fact, 'dictionary' was the second-most searched term on Ask.com in 2007.
"At the same time, Lexico's consumers frequently seek out a search engine immediately before and after using one of Lexico's sites.
"This acquisition expands Ask.com's reach and aligns perfectly with our customers' needs."
Brian Kariger, CEO and co-founder of Lexico, said: "This integration will give the Lexico sites a better consumer experience and [will be] even more useful for finding answers."
Terms of the deal were not disclosed. The transaction remains subject to customary closing conditions.