Orion was the great hunter. There are two main 'contenders' for his name and its origin. One is ouros, 'mountain' (the Ionic Greek form of oros), the other, bizarre though it may seem, is ouron, 'urine'. The 'mountain' origin could well be suitable for someone born in Boeotia, as Orion was - indeed it is a name that could apply to anyone from almost anywhere in Greece, which is a largely mountainous country.
The 'urine' origin is, inevitably, much more specific. The story was that Hyrieus, a Boeotian king who had no children, was advised by Zeus that if he wished for a child he should urinate on a bullhide. He did so, and Hermes and Poseidon buried it. Nine months later, a boy was born from the hide.
This was Orion. To support this account behind his name, Orion's name often featured in the form Urion. Yet a third explanation has been offered for the name, which derives it from orino, 'to be stirred', 'excite', with reference to his role as a hunter, or to the storms that he raised. The constellation of Orion was so named long ago, and certainly in Homer's time.