travel iron vs smoothing iron

travel iron and smoothing iron both are nouns.

Word	Noun	Adjective	Verb	Adverb
travel iron	Yes	No	No	No
smoothing iron	Yes	No	No	No

As nouns, smoothing iron is a hypernym of travel iron; that is, smoothing iron is a word with a broader meaning than travel iron:

travel iron: a small lightweight iron that can be carried while traveling
smoothing iron: home appliance consisting of a flat metal base that is heated and used to smooth cloth

Other hypernyms of travel iron include iron.

travel iron (noun)	smoothing iron (noun)
a small lightweight iron that can be carried while traveling	home appliance consisting of a flat metal base that is heated and used to smooth cloth