Certain areas on the map will be referred to with special names.
All possible spawn positions on the map are referred to as Main Bases. They usually offer plenty of space to place your supply, production and tech buildings.
Ramps, i.e. passages from low to higher ground, can be anywhere on the map. However, the expression your Ramp will usually refer to the ramp that is the entrance of your Main Base. Most current 1v1 Maps have a ramp leading up your Main Base.
Most maps have an expansion base just outside your Main Base. This base is referred to as the Natural, which was shortened from natural expansion, as the closest location is also the most natural to expand at.
Sometimes your Main Base will have a Ramp in front and another Ramp leading to a Natural at the back of the base that is inaccessible for the enemy, but frequently guarded by destructible rocks. This is called a Backdoor Natural. Having one of these might lead to you having two Naturals, a Front Natural and a Backdoor Natural. An example of this setup is Crevasse.
The Choke is a narrowed entrance to a base. Most of the time, your Natural will have a Choke that makes it easier to defend. Nerazim Crypt, for example, has a Choke at the Natural which is made very narrow by the presence of Destructible Rocks. Sometimes the entrance to your Main Base will also be referred to as your Choke; however, since most Main Base entrances are ramps, the expression is mostly used for the Natural.
High and Low Ground
Starcraft knows several height levels. Units cannot hit other units that are on a higher level without having gained vision of that level.
A Cliff is the High Ground territory that looms over a certain Low Ground. Your Cliff will most often refer to the Cliff above your Natural that needs to protected, as your opponent might try to exploit it with long range units like Siege Tanks. Air Units ignore Cliffs. Colossi and Reapers are able to scale cliffs without aid.