Confused about the meaning of nominal voltage

I have this solenoid:

Coil Voltage = 28VDC
Coil Voltage VDC NOM = 28V (I assume NOM means nominal?)

I asked earlier in this forum, and someone told me this should be run at 22 or 24 volts. However, I'm still confused. What does nominal mean, and why should I get a 24VDC power supply and not a 28VDC power supply to run it?

Sorry to ask clarification on this, but I am a musician and not an electrician. So much to learn!

I consider "nominal" to be roughly equivalent to "typical".

In the specific case of a solenoid, it will work over a wide range of voltages, but will overheat if you apply much higher than the nominal voltage and leave it on for long periods of time. For short periods of time, you can use significantly higher voltages and the solenoid will respond more quickly. At lower voltages it won't pull as hard and may not even close.

Check the solenoid data sheet for "duty cycle" information, which will tell you how long it can be left in the on state at a certain voltage.

I see. Thanks, that helps a lot. I'm thinking I should get more than 24 volt supply then, for these 28 volt solenoids.