1. A round-headed pin; a large nail, a spike. (m)
2. Hook of a hinge for doors and windows. (m)
3. Joint pin, crank pin. (Mecahnic) (m)
4. A bolt. (Nautical) (m)
- Perno de ojo -> eye-bolt
- Estar hasta el perno -> (And.) to be at the end of one's tether
estar hasta el perno (And) to be at the end of one's tether
What could we do to improve?