hothouse vs indoor garden

hothouse and indoor garden both are nouns.

Word	Noun	Adjective	Verb	Adverb
hothouse	Yes	No	No	No
indoor garden	Yes	No	No	No

As nouns, hothouse and indoor garden are synonyms defined as:

hothouse and indoor garden: a greenhouse in which plants are arranged in a pleasing manner

Other synonyms of hothouse include conservatory.

hothouse (noun)	indoor garden (noun)
a greenhouse in which plants are arranged in a pleasing manner	a greenhouse in which plants are arranged in a pleasing manner