Portal (noun)

1. A doorway, gate or entrance to a building, room, or enclosed space.
2. A website or application that serves as an entry point to a wide range of information and services.
3. A means of access or entry to a particular place or situation.

Origin:

From latin porta meaning "door, gate" from old french portail meaning "door, gate, entrance", first used in english in 14th century.

Examples:

1. The portal to the castle was heavily guarded.
2. The website serves as a portal to different news articles and resources.
3. They created a portal to another dimension.
4. The portal to the underworld was said to be guarded by Cerberus.
5. The university has a student portal where students can access their grades, schedules and other important information.