gateway

A passage that can be closed by use of a gate.

The original family who had begun to build a palace to rival Nonesuch had died out before they had put up little more than the gateway, […].

A place regarded as giving access to somewhere.

The staff offer a touch of Norfolk courtesy as they guide passengers onto connecting services. The bustling concourse has a wide selection of information and retail, including a very active city tourism presence. This station now feels like a real gateway to Norwich.

Any point that represents the beginning of a transition from one place or phase to another.

Any point that represents the beginning of a transition from one place or phase to another.

a gateway drug

Just as they say that marijuana leads to harder drugs, Gallegly is claiming that crush is a “gateway fetish”—a term I've never heard before. He claims that if someone starts with bugs they'll end up escalating to human babies in no time.

A point at which freight moving from one territory to another is interchanged between transportation lines.

To make available using a gateway, or access point.