WordWeb Online

1. Connecting without a break; within a common boundary
   "the 48 conterminous states";
   - contiguous
    
2. Having a common boundary or edge; abutting; touching
   "the side of Germany conterminous with France";
   - adjacent, contiguous, neighboring [US], neighbouring [Brit, Cdn]
    
3. Being of equal extent, scope or duration
   "All persons interested in the conterminous real estate shall be made parties to the petition";
   - coextensive, coterminous

See also: commensurate, connected