Legal definition of email

Is there anything that defines email for legal purposes? Some RFCs discuss electronic mail but without defining it. I came across a government site that accepts confidential information but says that emails are public information, and I suppose we all know an email when we see it, but many contact forms effectively send an email and when I go to my email service provider and compose an email that I then send I compose it in a form. So I wonder if the form is irrelevant to whether an online communication is an email. Is it only email if there’s an “@” in the address? If the content is sent through headers but without an “@” does that define it as not email? I’m not really asking substantive questions here; I’m trying to identify a source that already defines the term. Thanks.

1. I believe that all protocols should be reviewed with the web community/RFC and the community responsible for the protocol together with companies and public persons
2. About your question, the email protocol is made in RFC - however each company can implement email in the way it thinks best according to its business model or data security and privacy policy - most companies follow gdpr so that data is better managed
3. the @ symbol is for the email because whoever invented the email associated @ to the email
4. If you are concerned about privacy, an alternative is to use email with blockchain - but there are few companies that use this technology - I don’t want to nominate any company, but so… search for Protonmail or alternatives like Protonmail - it’s an encrypted email with free and paid plan