basis vs common ground

basis and common ground both are nouns.

Word	Noun	Adjective	Verb	Adverb
basis	Yes	No	No	No
common ground	Yes	No	No	No

As nouns, common ground is a hyponym of basis; that is, common ground is a word with a more specific, narrower meaning than basis:

basis: a relation that provides the foundation for something
common ground: a basis agreed to by all parties for reaching a mutual understanding

basis (noun)	common ground (noun)
the fundamental assumptions from which something is begun or developed or calculated or explained	a basis agreed to by all parties for reaching a mutual understanding
a relation that provides the foundation for something
the most important or necessary part of something