Sorites comes from the Greek word for “heap.” The sorites paradox exposes the problem of vague boundaries. One grain is not a heap; suppose adding a single grain can never turn a non-heap into a heap. Repeat the step and the argument concludes that no number of grains can make a heap.
The paradox is not solved by finding a universally correct grain count. It shows that apparently harmless judgments about every adjacent case can produce an absurd conclusion when repeated.