Search engine Ask.com, a unit of IAC/InterActiveCorp, has announced that it has closed an all-cash deal to acquire Lexico Publishing Group LLC, the owner of popular reference sites Dictionary.com and Thesaurus.com. The company said the deal expands its monthly audience by around 15 million users to 145 million, an increase of 11%, making Ask.com the ninth-largest Web property globally. The move comes as IAC announced plans to spin off four of its largest businesses and focus on Web media and advertising in coming months. Terms of the merger were not disclosed.