e-mail vs snail mail

e-mail and snail mail both are nouns.

Word	Noun	Adjective	Verb	Adverb
e-mail	Yes	No	Yes	No
snail mail	Yes	No	No	No

e-mail (noun)	snail mail (noun)
(computer science) a system of world-wide electronic communication in which a computer user can compose a message at one terminal that can be regenerated at the recipient's terminal when the recipient logs in	any mail that is physically delivered by the postal service

e-mail (verb)	snail mail (verb)
communicate electronically on the computer