mobile home vs house trailer

mobile home and house trailer both are nouns.

Word	Noun	Adjective	Verb	Adverb
mobile home	Yes	No	No	No
house trailer	Yes	No	No	No

As nouns, house trailer is a hypernym of mobile home; that is, house trailer is a word with a broader meaning than mobile home:

mobile home: a large house trailer that can be connected to utilities and can be parked in one place and used as permanent housing
house trailer: a wheeled vehicle that can be pulled by a car or truck and is equipped for occupancy

Other hypernyms of mobile home include housing, living accommodations, lodging, trailer.

mobile home (noun)	house trailer (noun)
a large house trailer that can be connected to utilities and can be parked in one place and used as permanent housing	a wheeled vehicle that can be pulled by a car or truck and is equipped for occupancy