Fluids can flow into something (a chamber, pipeline, manifold, etc.) through an opening called an inlet, and out of it through an opening called an outlet. However, in some cases, the flow could be reversed, such that opening that previously served as an inlet now serves as an outlet, and vice versa.
Is there a word (or few-word phrase) that can be used to describe such an opening (which might serve as an inlet, an outlet, or both), but that could not also be used to describe something other than such an opening?
Example sentence: Gas flows into and out of the chamber through its [word needed].
Words like opening and aperture could also be applied to many things which do not serve as an inlet and/or outlet. Words like channel and pipeline could similarly be applied to other things, but also are not hypernyms of inlet and outlet (since an inlet/outlet could be a simple opening, rather than a channel). Port has an analogous meaning in computer networking and electrical circuits, but seems to be specific to those fields (such that 'fluid port' would not carry the desired meaning). Thesaurus & dictionary searches for these words (and for inlet and outlet themselves) did not yield any other suitable candidates.
A similar question (Is there a word or phrase that combines the meanings of 'inlet' and 'outlet'?) is scoped to a social network context, and the answers provided there do not seem applicable to this fluid flow context.