frontier

Từ điển WordNet v3.1 - WordNet Dictionary

noun

1. a wilderness at the edge of a settled area of a country (Freq. 1)
- the individualism of the frontier in Andrew Jackson's day
• Hypernyms:
wilderness, wild
2. an international boundary or the area (often fortified) immediately inside the boundary
• Hypernyms:
boundary, bound, bounds
• Instance Hyponyms:
Triple Frontier
3. an undeveloped field of study;
a topic inviting research and development
- he worked at the frontier of brain science
• Hypernyms:
discipline, subject, subject area, subject field, field,
field of study, study, bailiwick