Not quite. Yes, there was a time when it was based on the "gold standard" but that really isn't done any more. It's based on trust, that if I do something for you and you give me this money stuff for doing it, I can use this money to buy other things and be sure that it will be accepted. I can trust it as something I can do swaps with.
You grow potatoes, I grow cabbages, I want some potatoes but you don't want my cabbages, We're stuck. But if we both agree that money has a value, I can give you some money in exchange for potatoes and I'm happy. Meanwhile you can exchange the money I've given you for something you DO want - carrots, maybe. Not surprisingly money got invented VERY early on in the history of civilisation. It makes trade SO much easier.
But in a way, it IS based on something of value. The value of money is that it REPRESENTS a store of wealth. Imagine a country that decides to print a trillion more dollars so everyone can be richer. All that will happen is that because it doesn't represent any more actual stuff that people can buy, stores will realise they can get away with charging more, so prices go up. All the country has achieved is to increase the rate of inflation. Duh!
This is exactly what happened in Zimbabwe some years ago when it was run by that prize idiot Robert Mugabe. He kicked white farmers off their land to replace them with black people, but it turned out the new farmers weren't so good at farming. The amount of food available dropped, so stores were able to charge more for it - in economics it's called "rationing by price". With prices going up, Mugabe's government decided to "help" by printing more money. All that happened was prices went up even more. Eventually there were so many zeroes on the end that the Zimbabwean dollar was revalued to keep the amounts looking sensible - twice. Meanwhile, people started using US dollars and South African rand because they're backed by sensible governments and you can trust them. Zimbabwean dollar bills are now only any use as kind of interesting wallpaper.
The real problem, as you can see, is the government attacking the wrong problem. The real problem is not enough food, and playing with the money doesn't make anyone produce any more. The thing to do was TRAIN THE FARMERS! Zimbabwe CAN feed itself if it does that. Hopefully the new government under President Mnangagwa will do that.
See? It IS based on something, but it's kind of indefinable. It's worth what you can do with it. In the 1980s, Margaret Thatcher tried to keep inflation down in the UK by doing the opposite - deliberately restricting the growth of the money supply. The result was painful because unemployment went up but it DID work in the end. Which is an interesting thing in economics - it seems to be impossible to reduce inflation AND unemployment at the same time. She went for tackling inflation first and then everyone who lost their jobs (and others) hated her, but it took time to do both.