A place ships come in, and a numbered doorway a system listens on. Also to carry a thing across to a new ground.
Latin portus (a harbor), related to porta (a gate) and portare (to carry); a controlled point where passage happens, whether for ships, signals, or software carried to new ground.
A controlled point of passage — a harbor for ships, a numbered doorway a system listens on, or the carrying of a thing across to new ground.