A pin inserted through holes at the end of an axle or shaft, so as to secure a wheel or shaft-mounted device.
A central cohesive source of stability and security; a person or thing that is critical to a system or organisation.
To adopt as, or serve as, a central cohesive source of stability and security.
A pin in the form of a clasp, which has a guard to cover the sharp point; used to join two pieces of fabric, etc., together temporarily.
The pin of a hand grenade, which prevents accidental detonation.