"Eph" is not a standard abbreviation in physics. It's possible you're thinking of a different term or abbreviation, or perhaps it's specific to a particular context or field within physics.

To help me understand what you're looking for, could you provide more information? For example:

* Where did you see this abbreviation? (A textbook, a research paper, a lecture, etc.)

* What was the context? (What was being discussed or described?)

* What did you think "eph" might refer to?

With more context, I can help you figure out what "eph" means in physics.