The phrase "abut on" means to border or adjoin. Some common synonyms for this expression include "touch," "meet," "butt up against" and "border on." Other options include "neighboring," "flanking," "adjacent to," and "nearby." "Abut on" can also be substituted with "join," "connect," or "link up with." When describing two objects that share a common boundary, "abut on" can be replaced with "be contiguous with," "lie beside," or "be coterminous." Some less common, more specific synonyms include "march," "interlock," and "embrace." Ultimately, the synonym chosen will depend on the context of the situation.