A hot rod is a really cool, often expensive, and super fast car that people like to customize and make faster. It's like when you get a toy car and you want to add extra cool things to it, like stickers, bigger wheels or a spoiler. But instead of just making it look cool, people who make hot rods want to make it go super fast too. They change the car engine, put in special parts and add other things to make the car super speedy.
It's like when you pedal your bike really fast and try to go as fast as you can. Only, hot rods are much faster than your bike, and the people who own them like to show them off to other people who like hot rods too. Sometimes they will race them to see whose car is the fastest.
Hot rods are not just fast, though. They're also really unique and can look really different from normal cars. They're like a special kind of car that people love to admire and work on. It can take a lot of time and money to build a hot rod, but people who love them think it's totally worth it.