noun
email
A1
'E-Mail' (die) means an email message or electronic mail. It's a feminine German loanword (from English) often shortened to 'Mail'. Plural is 'E-Mails' (die E-Mails). Typical forms: die E-Mail, der E-Mail (dative/genitive contexts). Used widely in informal and formal communication.
Examples
Ich habe dir eine E-Mail geschickt.
I sent you an email.
Als die Kundin die E-Mail öffnete, bemerkte der Assistent einen Fehler, weil die Adresse falsch war.
When the customer opened the e-mail, the assistant noticed a mistake because the address was wrong.
Ich habe dir gestern eine E-Mail geschickt.
I sent you an email yesterday.
Details
Mnemonics
Picture an envelope with an @ sign to remember E-Mail
same as English 'email', just with a hyphen
die — think 'die Nachricht' (the message) which is feminine
Notes
E-Mail often takes the plural E-Mails. In some usage neuter appears, but standard article is die.