For example suppose a feature in an object or a human that distinguishes the object from the rest, what are the constructions to say this sentence?
We define an anchor as a textual element that marks the start or end of a data region, or as a distinctive feature within a region that distinguishes it from the rest of the page.
.... that makes it distinguishable from the rest.
distinctivefeature within a region that makes it distinctive.
Are there shorter ways to say that?