any of various varnish resins, consisting of the exudates obtained from various tropical trees. The name copal was probably derived from the Nahuatl copalli, "resin." When hard, copal is lustrous, varying in hue from almost colourless and transparent to a bright yellowish brown. It dissolves in alcohol or other organic solvents upon heating and is used in making varnishes and printing ink. Copal is obtained from various sources; the term is vaguely used for resins that, though similar in physical properties, differ in their chemical makeup and are altogether distinct as to their source
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