mail vs letter

mail and letter both are nouns.

Word	Noun	Adjective	Verb	Adverb
mail	Yes	No	Yes	No
letter	Yes	No	Yes	No

mail (noun)	letter (noun)
(Middle Ages) flexible armor made of interlinked metal rings	a written message addressed to a person or organization
a conveyance that transports the letters and packages that are conveyed by the postal system	the conventional characters of the alphabet used to represent speech
the system whereby messages are transmitted via the post office	an award earned by participation in a school sport
the bags of letters and packages that are transported by the postal service	a strictly literal interpretation (as distinct from the intention)
any particular collection of letters or packages that is delivered	owner who lets another person use something (housing usually) for hire

mail (verb)	letter (verb)
cause to be directed or transmitted to another place	mark letters on or mark with letters
send via the postal service	set down or print with letters
	win an athletic letter