I looked it up. Pretty sure we didn't learn that in high-school. I was in advanced math and science classes through pre-calculus and advanced biology and I don't ever recall learning that.
I still don’t know what it is and have gotten by just fine without it.
Did you ever attempt to plug a 110 volt appliance into your cigarette lighter?
Or go to an internet forum to find out if it would work?
Appliance, no. 110V impact wrench on a 400 watt inverter a few times. Didn't have a 12V plug for my laptop so I've plugged that into a 400Watt inverter as well.
I can walk on water.......................but I do stagger a bit on alcohol.