a. [ L. glacialis, from glacies ice: cf. F. glacial. ] 1. Pertaining to ice or to its action; consisting of ice; frozen; icy; esp., pertaining to glaciers; as, glacial phenomena. Lyell. [ 1913 Webster ]
2. (Chem.) Resembling ice; having the appearance and consistency of ice; -- said of certain solid compounds; as, glacial phosphoric or acetic acids. [ 1913 Webster ]
Glacial acid (Chem.), an acid of such strength or purity as to crystallize at an ordinary temperature, in an icelike form; as acetic or carbolic acid. --
Glacial drift (Geol.), earth and rocks which have been transported by moving ice, land ice, or icebergs; bowlder drift. --
Glacial epoch or
Glacial period (Geol.), a period during which the climate of the modern temperate regions was polar, and ice covered large portions of the northern hemisphere to the mountain tops. --
Glacial theory or
Glacial hypothesis. (Geol.) See Glacier theory, under Glacier. [ 1913 Webster ]