Or just Choke. A location on the game map where the topography restricts access to an attacking force in favour of a defending force. This is an area that is easily defended at relatively little cost, but expensive for the enemy to capture once fortified. e.g.: a mountain pass, or a shallow point that is accessible through a river. Any attackers are forced into a bottleneck and thus vulnerable to any entrenched and protected defensive fire. Chokes can make or break invasions, letting a small force stop or destroy one that is considerably bigger and nastier than itself. Any mug who thinks that all there is to winning RTS is building the biggest army fastest and then rushing the enemy obviously hasn't blundered into a well defended choke, or only plays maps that permit unrestricted movement. If the game allows the creation of walls or other obstacles, you can build your own chokes as effective defences around your base.

a group of civilian and military facilities

a leverage point that can work against us

a channel capturing the entire flow of a current and is considered a prized phenomenon in oceanographic circles

a traffic jam, a congested area, a place to keep alert

a place that is a path that only leads one way, and is very small

a place where there is only one way thru and where there are few options