edge vs butt on

edge is a noun but butt on is not a noun.

Word	Noun	Adjective	Verb	Adverb
edge	Yes	No	Yes	No
butt on	No	No	Yes	No

As verbs, edge and butt on are synonyms defined as:

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

edge (noun)	butt on (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)	butt on (verb)
lie adjacent to another or share a boundary	lie adjacent to another or share a boundary
provide with an edge
advance slowly, as if by inches
provide with a border or edge