telco building vs building

telco building and building both are nouns.

Word	Noun	Adjective	Verb	Adverb
telco building	Yes	No	No	No
building	Yes	No	No	No

As nouns, building is a hypernym of telco building; that is, building is a word with a broader meaning than telco building:

telco building: a building that houses telecommunications equipment
building: a structure that has a roof and walls and stands more or less permanently in one place

Other hypernyms of telco building include edifice.

telco building (noun)	building (noun)
a building that houses telecommunications equipment	the act of constructing something
	the commercial activity involved in repairing old structures or constructing new ones
	a structure that has a roof and walls and stands more or less permanently in one place
	the occupants of a building