creek bed vs dry wash

creek bed and dry wash both are nouns.

Word	Noun	Adjective	Verb	Adverb
creek bed	Yes	No	No	No
dry wash	Yes	No	No	No

As nouns, dry wash is a hyponym of creek bed; that is, dry wash is a word with a more specific, narrower meaning than creek bed:

creek bed: a channel occupied (or formerly occupied) by a stream
dry wash: the dry bed of an intermittent stream (as at the bottom of a canyon)

Other hyponyms of creek bed include wash.

creek bed (noun)	dry wash (noun)
a channel occupied (or formerly occupied) by a stream	the dry bed of an intermittent stream (as at the bottom of a canyon)