What is "what is more"

adv. (context idiomatic English) furthermore, or in addition, moreover. alt. (context idiomatic English) furthermore, or in addition, moreover.

adv. in addition; "computer chess games are getting cheaper all the time; furthermore, their quality is improving"; "the cellar was dark; moreover, mice nested there"; "what is more, there's no sign of a change" [syn: furthermore, moreover]