The Collaborative International Dictionary of English v.0.48:
Methylated \Meth"yl*a`ted\, a. (Chem.) Impregnated with, or containing, methyl alcohol or wood spirit; as, methylated spirits. [1913 Webster]WordNet (r) 3.0 (2006):
methylated adj 1: having received a methyl group; "methylated alcohol"