What is a chat versus a message?
You will understand these two words so ChatGPT feels less confusing.
A message is one thing you type and send. It is like one note.
A chat is the whole conversation. It is made of many messages, yours and the ones ChatGPT sends back.
Think of it like talking with a friend. Each thing you say is a message. The full talk is the chat.
Buddy says
One chat can hold many messages. You can keep typing in the same chat all day.