Webster 1913 Edition
Any of a group of three metameric hydrocarbons of the aromatic series, found in coal and wood tar, and so named because found in crude wood spirit. They are colorless, oily, inflammable liquids,
C6H4.(CH3)2, being dimethyl benzenes, and are called respectively
paraxylene. Called also
☞ Each of these xylenes is the nucleus and prototype of a distinct series of compounds.