an alcohol-soluble gum resin taken from various grass trees, used in varnishes, etc.: unique among natural resins because it forms a hard, insoluble, chemical-resistant film when heated
See acaroid resin in American Heritage Dictionary 4
noun
A yellow or reddish resin obtained from various Australian grass trees and used in varnishes, lacquers, and paper manufacture. Also called accroides gum, gum accroides.