Definitions

1. noun

A salmonid fish, especially the anadromous form of the rainbow trout (Oncorhynchus mykiss), that migrates from saltwater to freshwater to spawn.

“The fisherman caught a large steelhead in the river.”

2. noun

A steelhead trout that has been raised in a hatchery and released into the wild.

“The researchers studied the behavior of the hatchery-raised steelhead.”