big top vs canvas

big top and canvas both are nouns.

Word	Noun	Adjective	Verb	Adverb
big top	Yes	No	No	No
canvas	Yes	No	Yes	No

As nouns, canvas is a hypernym of big top; that is, canvas is a word with a broader meaning than big top:

Other hypernyms of big top include canvas tent, canvass.

big top (noun)	canvas (noun)
a canvas tent to house the audience at a circus performance	a heavy, closely woven fabric
	the mat that forms the floor of the ring in which boxers or professional wrestlers compete
	a tent made of canvas fabric
	a large piece of fabric (usually canvas fabric) by means of which wind is used to propel a sailing vessel
	an oil painting on canvas fabric
	the setting for a narrative or fictional or dramatic account

big top (verb)	canvas (verb)
	cover with canvas