An isolate is the pure form of a single cannabinoid, separated from everything else that was in the plant. Most often that is CBD.
It comes from carrying distillation further: the distillate is dissolved, left to crystallise, and the crystals are washed. What you end up with is a white powder or translucent crystals with no smell and no taste.
In practice that lets you count precisely. A producer knows exactly how much of what went in, because there is nothing else in the raw material. So isolate is used wherever a composition is declared down to the milligram.
The opposite is Full-Spectrum Extract, which deliberately keeps the original make-up of the plant.
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