hard disc vs fixed disk

hard disc and fixed disk both are nouns.

Word	Noun	Adjective	Verb	Adverb
hard disc	Yes	No	No	No
fixed disk	Yes	No	No	No

As nouns, hard disc and fixed disk are synonyms defined as:

hard disc and fixed disk: a rigid magnetic disk mounted permanently in a drive unit

Other synonyms of hard disc include hard disk.

hard disc (noun)	fixed disk (noun)
a rigid magnetic disk mounted permanently in a drive unit	a rigid magnetic disk mounted permanently in a drive unit