The Collaborative International Dictionary of English v.0.48:
Acetal \Ac"e*tal\, n. [Acetic + alcohol.] (Chem.) A limpid, colorless, inflammable liquid from the slow oxidation of alcohol under the influence of platinum black. [1913 Webster]WordNet (r) 3.0 (2006):
acetal n 1: any organic compound formed by adding alcohol molecules to aldehyde molecules