glacial

Concise Oxford English Dictionary © 2008 Oxford University Press:
glacial /ˈgleɪsɪəl, -ʃ(ə)l/

▶adjective

• 1 relating to ice, especially in the form of glaciers.

• 2 extremely cold.

  ■ unfriendly or unemotional.

• 3 Chemistry denoting pure organic acids (especially acetic acid) which form ice-like crystals on freezing.

▶noun Geology a glacial period.

– derivatives
glacially adverb.

– origin C17: from Fr., or from L. glacialis ‘icy’.