Nouns in this dictionary sit in an inheritance hierarchy: each sense has broader terms (the categories it is a kind of) and narrower terms (the kinds of it). A collie is a kind of shepherd dog, which is a kind of working dog, which is a kind of dog, which is a kind of domestic animal, which is a kind of animal. The relation holds between senses, not between spellings — which is where most attempts to follow a chain go wrong.
Two relations, one test
A broader term names the category a sense belongs to. A narrower term names a subtype of it. Lexicographers call them hypernyms and hyponyms; the test for both is the same sentence.
Say “an X is a kind of Y”. If that reads as true, Y is broader than X. A poodle is a kind of dog: true, so dog is broader. A dog is a kind of poodle: false. The relation only runs one way, and that asymmetry is what makes it a hierarchy rather than a web.
It also inherits. If a poodle is a kind of dog and a dog is a kind of animal, a poodle is a kind of animal, without anyone recording that link directly. Everything true of the category is true of everything under it, which is the whole reason the structure is worth having.
Three chains, as recorded
These are read directly off the entries. Each arrow is one recorded broader-term link, and every step in each chain is one you can check by opening the word.