A company whose revenue is primarily derived from a technology characterized by high margin, high scalability and low fixed costs. One could also say that such a technology should be the primary differentiator for the product. The products therefore tend towards software and hardware as applied to a pre-existing market, but that's not an ironclad rule.
So for example not Tesla (high fixed costs, low margin), not Uber (negative margin), and not Amazon (the retail part is low margin; AWS actually fits).
And things like Wish clearly only if we're talking gross margin, not operating margins. The amount of ads they're running is crazy.