funeral vs sky burial

funeral and sky burial both are nouns.

Word	Noun	Adjective	Verb	Adverb
funeral	Yes	No	No	No
sky burial	Yes	No	No	No

As nouns, sky burial is a hyponym of funeral; that is, sky burial is a word with a more specific, narrower meaning than funeral:

funeral: a ceremony at which a dead person is buried or cremated
sky burial: a traditional Tibetan funeral ritual in which the corpse is exposed to the open air to be eaten by sacred vultures

Other hyponyms of funeral include burial, entombment, inhumation, interment, sepulture.

funeral (noun)	sky burial (noun)
a ceremony at which a dead person is buried or cremated	a traditional Tibetan funeral ritual in which the corpse is exposed to the open air to be eaten by sacred vultures