E-mail or an e-mail?

Hi!

I have a question.

The word 'letter' is countable while 'mail' is uncountable. When I wrote 'I sent e-mail to my mother.' an American friend of mine told me that I should put an article 'an' like 'an e-mail.' But should I?

Thank you.

K. Yonehara

E-mail is short for "Electronic Mail".
So it's as if you were to say:
"I sent electronic mail to my mother." ..sounds right.
But with the article you would have to say:
"I sent an electronic letter to my mother."
"Electronic" is just an adjective.
Same rules apply if you were to change the adjective to "overnight"
"I sent overnight mail to my mother." Or "I sent an overnight letter/package to my mother."
HOWEVER: The word "E-mail" has become an accepted euphemism for the word "letter" even though it technically means Mail". So, you're right grammatically but your friend is right in common usage.

Surely e-mail implies an indeterminate number of electronic messages whereas 'an email' implies just one such message. Hence I can receive 'e-mail' (one or more messages) or I can receive an 'e-mail' message. Well, that's how I understand it this morning in SW1; could get grammatically technical but my pedantic libido is low.