What is a word that describes both "entry" and "exit"?

Solution 1:

An Access or Accessway

accessway: a path, route, etc., that provides access to a specific destination or property, as to a public beach or state park

Solution 2:

How about door? From Lexico:

door: A hinged, sliding, or revolving barrier at the entrance to a building, room, or vehicle, or in the framework of a cupboard

Doors are entrances to interior spaces and exits to exterior spaces. That is, they address both entry and exit, depending on one's direction of travel.

Solution 3:

In the context of buildings, @RichardKayser's suggestion of doors/doorways probably makes the most sense.

In more general circumstances, another word of use, defined via Merriam-Webster, is

passageway: a way that allows passage

Entrances and exits enable passage between spaces.