In a lock tumbler, the opening for the stump of the bolt to pass through or into.

The part of the karibiner that opens.

(n.) A notch cut into the edge of a tumbler to accept a fence or sidebar. Source: Lock Industry Standards and Training (LIST) Council

An open/closed switch

See Lock Gate

an object with two states, open and closed

The section of a karabiner which opens

1. An open gate is a harbinger of promising opportunities in the near future. 2. Dreaming of a closed gate is an obstacle dream. However, the obstacles can be overcome if you work hard at it. To judge exactly what obstacles you face, look to other symbols in the dream. 3. A locked gate implies obstacles that are practically impassible, unless in the dream you also find ways to go over it, under it, or around it. In the latter case, success is practically guaranteed.

The spring-loaded opening on a carabiner. Can be straight or bent, locking or non-locking.

Gateway in the wall or fort protecting the city, which may be opened to let in friends or closed to keep out enemies. It would normally consist of a gate in the outside wall, a room-sized space, then a furtits door through the inner wall into the interior.

the opening through which a moulding compound is injected into a closed mould; the size, geometry and positioning of the gate can strongly influence properties of the finished moulding