Gmail – What exactly is a conversation in Gmail

gmailgmail-conversations

Apologies if this has been already answered somewhere here, but I really can't understand/find what is the actual notion of conversation in Gmail.

According to Google:

Gmail groups all replies with their original message, creating a single conversation or thread.

Anyway I have seen that sending two emails with the same "Merry Xmas" subject groups them in a conversation too.

Where can I find a formal definition of conversation or, put it differently, what are the rules to group message A and B under the same conversation?

Best Answer

Replies to emails and forwards of emails make up conversations.

When a subject is changed, that breaks the conversation.

For some reason, e-mails with the same title may get grouped into a conversation.

However, there isn't a way that I know of to group individual emails into a conversation.