1. [verb] (transitive) To make tighter.
2. [verb] (intransitive) To become tighter.
3. [verb] (economics) To make money harder to borrow or obtain.
4. [verb] (economics) To raise short-term interest rates.
5. [verb] Make tight or tighter; 'Tighten the wire'.
6. [verb] Become tight or tighter; 'The rope tightened'.
7. [verb] Restrict; 'Tighten the rules'; 'stiffen the regulations'.
8. [verb] Narrow or limit; 'reduce the influx of foreigners'.
