If it's black, and connected to a ring lug, then yes, it's ground. Or you could be an early 2003 model with the 2002 harness in there that would support the underhood lamp, which they de-contented in 2003 to save a buck.
You can track that ground wire from the base of the hood back to a larger harness nearby and then out of that harness to a vehicle firewall ground. The remainder of the wires in the harness go through a firewall grommet to inside the cabin.
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