My house is over 100 years old and still running. But my toilet on the other hand 🪠 has this quirk, the cistern will not full until the sink tap runs, you might say it's synchronous 😏.
Asynchronous is like everyone else's house where the water runs at the same time for all toilets and taps.
... I don't know what to do with this info but you can apply it to your programming knowledge, things happen one after the other or things that happen at the same time, async and sync are concepts of time and with, it's time for me to go.