Parthian coinage is like the money that people in ancient Parthia used a long time ago. Ancient Parthia was a place where people lived a really long time ago, just like playing a game with your friends where you pretend to be kings and queens.
Parthian coins are like little round pieces of metal that people used to buy things or trade them for other things they needed. They had pictures of people or animals or symbols on them, kind of like the stickers or drawings you like to put on your notebooks.
The coins were made of different kinds of metal, like bronze, silver, and gold. Some were worth more than others. It's like how in your currency, you may have a $1 bill and a $10 bill, and the $10 is worth more.
People had to be careful with these coins because they were valuable and there were people who would try to steal them. So, just like how you might put your money in a piggy bank or a safe, people in Parthia would keep their coins in special places to make sure they didn't get lost or stolen.
Nowadays, Parthian coins are really old and valuable, kind of like how your toys may become collectibles someday for someone else. People who study history like to learn about these coins because they tell us things about how people lived a long, long time ago.