Have you ever chatted with someone and in the course of the chat the person used something like zzz but you literally did not understand what it meant. Do you really want to know why and what the use of zzz stand for in a chat. Don't worry, you are getting the answer very soon. zzz is a sign used when chatting to depict the sender is feeling sleepy or getting bored or tired.
The use of zzz is also common in comic books, if you read comic books, you would already have an idea. It is used in media where sound effects are not present. The slang word is often used online especially on online chats e.g whatsapp, facebook and emails. Zzz is mostly used at the end of a sentence, you can represent everything in lower or upper depending on how you like it