What is Latin for "relate"?

Question

I mean that sense of relate which we find in:

A relates to B as C does to D.

or when we speak of A and B's relation, meaning whatever may be said of A and B without further specification.

If forced to give a definition, I would say that A's relation to B is how A stands to B, which is a metaphor (is it?) and couldn't possibly tell someone who didn't already know what a relation was.

Background

Referō does not seem to have this sense.

Perseus only seems to give Latin words for other senses: relate, relation.

Answer 1

How about the verb contingere? One of the meanings (L&S: II.B.2) is "to be connected with or related to, to concern". I suggest this translation for your example (with slight changes to make cases visible):

The first thing relates to the second as the third one does to the fourth.
Res prima secundam contingit sicut tertia quartam.

If you want to say that the first thing relates to the second one in size or some other quality, you can add an ablativus respectus to give details: Res prima magnitudine secundam contingit…