Definition of vast

• unusually great in size or amount or degree or especially extent or scope; "huge government spending"; "huge country estates"; "huge popular demand for higher education"; "a huge wave"; "the Los Angeles aqueduct winds like an immense snake along the base of the mountains"; "immense numbers of birds"; "at vast (or immense) expense"; "the vast reaches of outer space"; "the vast accumulation of knowledge...which we call civilization"- W.R.Inge