Wordnet 3.0
VERB (1)
1. 
 lie adjacent to another or share a boundary; 
- Example: "Canada adjoins the U.S."- Example: "England marches with Scotland"[syn: border, adjoin, edge, abut, march, butt, butt against, butt on]
WordNet (r) 3.0 (2006):
butt on
    v 1: lie adjacent to another or share a boundary; "Canada
         adjoins the U.S."; "England marches with Scotland" [syn:
         border, adjoin, edge, abut, march, butt, butt
         against, butt on]