edge vs adjoin

edge is a noun but adjoin is not a noun.

Word	Noun	Adjective	Verb	Adverb
edge	Yes	No	Yes	No
adjoin	No	No	Yes	No

As verbs, edge and adjoin are synonyms defined as:

Other synonyms of edge include abut, border, butt, butt against, butt on, march.

As verbs, adjoin is a hypernym of edge; that is, adjoin is a word with a broader meaning than edge:

Other hypernyms of edge include contact, meet, touch.

edge (noun)	adjoin (noun)
a sharp side formed by the intersection of two surfaces of an object
the outside limit of an object or area or surface; a place farthest away from the center of something
a slight competitive advantage
the attribute of urgency in tone of voice
the boundary of a surface
a line determining the limits of an area

edge (verb)	adjoin (verb)
lie adjacent to another or share a boundary	attach or add
provide with an edge	lie adjacent to another or share a boundary
advance slowly, as if by inches	be in direct physical contact with; make contact
provide with a border or edge