Gla"cial (?), a. [L. glacialis, from glacies ice: cf. F. glacial.]
Pertaining to ice or to its action; consisting of ice; frozen; icy; esp., pertaining to glaciers; as, glacial phenomena.
Resembling ice; having the appearance and consistency of ice; -- said of certain solid compounds; as, glacial phosphoric or acetic acids.
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 ∨ 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 ∨ hypothesis. Geol. See Glacier theory, under Glacier.
© Webster 1913.