| 1. | U.S. History. the slave states of Delaware, Maryland, Kentucky, and Missouri, which refused to secede from the Union in 1860–61. |
| 2. | the U.S. states touching the Canadian border. |
| 3. | certain countries of central and northern Europe that border on the former Soviet Union and belonged to the Russian Empire: Finland, Poland (prior to 1940), Estonia, Latvia, and Lithuania. |
| Main Entry: | border state1 |
| Part of Speech: | n |
| Definition: | any of the southern slave states of the U.S. Civil War that bordered the northern free states (Delaware, Kentucky, Maryland, Missouri, Virginia) |
| Main Entry: | border state2 |
| Part of Speech: | n |
| Definition: | a U.S. state bordering on Canada or Mexico |
| Main Entry: | border state3 |
| Part of Speech: | n |
| Definition: | a country that borders on a larger more powerful country; a country that lies between two larger countries |