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
based on custom rather than documentation; "an unwritten law"; "rites...so ancient that they well might have had their unwritten origins in Aurignacian times"- J.L.T.C.Spence