canopy vs baldachin

canopy and baldachin both are nouns.

Word	Noun	Adjective	Verb	Adverb
canopy	Yes	No	Yes	No
baldachin	Yes	No	No	No

As nouns, baldachin is a hyponym of canopy; that is, baldachin is a word with a more specific, narrower meaning than canopy:

canopy: a covering (usually of cloth) that serves as a roof to shelter an area from the weather
baldachin: ornamented canopy supported by columns or suspended from a roof or projected from a wall (as over an altar)

Other hyponyms of canopy include awning, sunblind, sunshade, marquee, marquise, porte-cochere, tester, umbrella.

canopy (noun)	baldachin (noun)
a covering (usually of cloth) that serves as a roof to shelter an area from the weather	ornamented canopy supported by columns or suspended from a roof or projected from a wall (as over an altar)
the umbrellalike part of a parachute that fills with air
the transparent covering of an aircraft cockpit

canopy (verb)	baldachin (verb)
cover with a canopy