Not trying to start a flame war here, but I have to side with Robert Meier:
NOBODY in electrical industry calls it 110/220 anymore, for two simple reasons: 120/240 is the de-facto industrial standard, and NEC uses that as a nominal voltage.
It does NOT mean that if you stick multimeter probes into an average outlet in the US you will get 120 volts every time; However, when referring to the standard residential service, the proper way to call it is 120/240.
To put it differently: seeing a home inspector call it 110/220 in writing on the report (provided of course that’s what you do, Bob) is just as off-putting and detracting from the impression of the document as glaring typos and grammatical errors.
Not bashing anybody but I agree. Just putting my thoughts in. 120/240 or 120/208 is the standard reference since its the nominal voltage strived for at any device. For example when setting a back up generator the voltage governor in it is programed/designed for a 120 volt constant output under varying load. Voltage will drop by about a few volts at say the light fixture but its closer the average voltage we try to keep at equipment. 110/220 actually comes from the old days of electrification. Power was actually 110 and 220 and 480 was kept at a median average of 460. Over time it went up as well as the rating of equipment, ie older devices may be labelled as 115 then 117 and now 120.
A bit of irony though. Motors to this day are still listed at a lower voltage like 460 volts with the intent to work well with voltage drop on a 480 volt system. But in the end it works out ok regardless.
Mike has some great ideas some times ,but he is convinced he is the best,
He, I think is some sort of an engineer.
They way he some times acts It looks like he is a sanitary engineer
( You Know a garbage collector ) .
It is obvious he is extremely jealous of me and some others .
I expect he will attack me and this post ,
Fortunately for me I can not see his posts .