WordWeb Online

1. A wilderness at the edge of a settled area of a country
   "the individualism of the frontier in Andrew Jackson's day"
    
2. An international boundary or the area (often fortified) immediately inside the boundary
    
3. An undeveloped field of study; a topic inviting research and development
   "he worked at the frontier of brain science"

Derived forms: frontiers

Type of: bailiwick, bound, boundary, bounds, discipline, field, field of study, study, subject, subject area, subject field, wild, wilderness

Encyclopedia: Frontier, MI Frontier, Michigan Frontier Frontier, American Frontier, Saskatchewan Frontier, Wyoming Frontier, ND Frontier, North Dakota