What does re mean in mail

In email, "re" is an abbreviation for "regarding" or "in response to". It is often used as a prefix to indicate that the email is a reply to a previous email or message.

For example:

The "re" prefix is commonly used in email subject lines and in the body of the email to indicate that the message is a response to a previous message. It is a shorthand way of saying "regarding" or "in response to", and it helps to quickly convey the context of the email.

It's worth noting that "re" is not an abbreviation for "reply", although it is often used in a similar way. The word "reply" is a verb that means to respond to a message, while "re" is a prefix that indicates that the message is a response to a previous message.