What is a creek bed exactly is it just a different name for creek channel?

I've always just thought of it as the ground under the water

A creek channel is the 'remains' of a creek that's under the surface of a reservoir.

A creek bed is the bottom of a creek that's still just a creek.

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 

Over the length of the creek. The bed, floor composition can/will change. Maybe rock, gravel, silt, slab rock. 

57 minutes ago, MN Fisher said:

A creek channel is the 'remains' of a creek that's under the surface of a reservoir.

A creek bed is the bottom of a creek that's still just a creek.

 

Or... a dry creek bed such as you would find in arid places.

 

P.S. I've never caught anything in them and they are hard on lures!

Creek channel , creek bed  when it comes to bass fishing terminology same thing . Wait , I never heard of bed bends . ?