It's common on many electronic instruments (SMUs, DVMs, electrometers, picoammeters, LCR bridges, etc.) to have a guard terminal, sometimes a passive guard and sometimes an active, driven guard. Some instruments have both (e.g. some LCR bridges, many SMUs) but I've never seen an instrument that explicitly brings both guard types out as individually labelled terminals - those kind of instruments usually have the guard on the secondary shield of a triaxial connector (e.g. Keithley 236 SMU).
If there was an instrument which brought out both a passive guard (typically associated with a LO terminal) and an active driven guard (typically associated with HI terminals) to individually labelled terminals, how would you expect those terminals to be labelled?
As the question implies, I'm interested in your expectation of what the labels would be. I'm trying to pick labelling that would be understood by most people without further explanation (implicitly, people who already know what a guard terminal is).
I've already got a thought of what I'd use, but I don't want to prejudice people's answers.