Typically a 220 volt labeled dryer is an older one
The nominal voltages to houses has just gone up and thus eons ( a century ago! ) stuff was labeled 110 volts or 220 volts.
Later dialog was 115 and 230 volts, or 117 and say 235 volts.
Even later stuff is labeled 120 and 240 volts.
In slang saying one is using 220 volts often means one has been around awhile. The actual voltage one has at an outlet varies by location of the country, location to the sub station, time of day, air temperature is folks are using their AC units.
The 240 volt here at my business is typically about 242 to 243 volts and sags to 235 to 230 in the summer during a passive peak hot day. One big machine has "taps" where one can set the input lugs to be 240, 230, 220 or 208 depending one ones local conditions, 208 is for 120/208 Y .
Older dryers in the USA are actually often labeled 110/220 volts if from the 1940's to even 1960's.
My 1976 dryer has 240 volts, 208 volts in Y, and 120 volts on its patent plate. Other machines in that era often say 115/230 volts too.
A dryer coil kit for my 1976 Westinghouse comes precut for an obscure 255 volts as is. Yes 255 Volts. This is obscure.
One has this coiled giant spring like NiChrome coil that is about say 6 feet long. One cuts off a few inches to run it at 240 volts, a tad more for 230 volts, a tad more for 220 volts, and a tad more for 208 volts. This is in the offical Westinghouse coil kit.
When I was a kid the house's lines were called a 220 volt lines. Most older motors and ones stuff was called 110 volts. One still Today has socket adapters at Home Depot that convert an Edison bulb socket to a 2 prong plug. These are often labeled 660 watts max, this goes back over 100 years. It is from 6 amps at 110 volts. This was the max load with many plugged things 100 + years ago.
Here I have several old AC induction motors in my junk box that are labeled 220 volts and even a 30 amp 220 volt watt hour meter and a 110 volt 30 amp watt hour meter for a house.
In a California Apartment I had awhile back in the 1990's, the nominal 120/240 volts of today was never that low. I was right by the substation a the start of the feeder and the voltage was about 126 to 127 normally. I never saw it go below 122, once it was at 132 volts.
When I lived in the Midwest in the early 1960's at the end of a feeder our houses "220 or 230 volts" was normally closer to 220 volts. One has a massive amount of legal things as to what was actually required to be delivered to a house or business and often in the past it was lower.
220 volts was once the NORM in the USA eons ago, it just went to 230 then later to 240 volts. In the 110/ 220 volt era the bulk of the stuff sold was marked that way, a good swag is this is mostly pre WW2 stuff. Thus my pre WW2 Westinghouse Copper cozy glo heater is marked 110 volts and 5 amps.
Not all old 220 volt AC motors will/would tolerate running on 240 volts, thus power companies if the raised the nominal from 230 to 240, one old plant might have a transformer with its input taps set lower to serve the older motors.
If one looks at the USA a century ago, there was no 230 or 240 volts, it was 220 volts and 110 volts. Even a 1930's EE book has the voltage on the poles as 2200 volts or 440 volts and the supply to the factory is 110 /220 volts.
The USA old voltage standards of 110, 220 and 440 volts goes back to the Tesla AC days and his war with Edisons 90 to 110 volts DC.
A 1880's lamp with a carbon filament sort of set the rough spec, it was about 100 volts. If one went higher the filment got very fragile. 110 was the voltage more like at the begining of a line.
If one looks at watt hour meters from 100 years ago for houses and buildings houses were mostly 110 volt units and a small business had a 220 volt meter with 2 hot wires.
In the 1940's watt hour meters I have on some AC units and big equipment, the nameplate is either 230 volts or 240 volts