means Letters, parcels, and other communications sent and delivered through a postal system, or the system itself.

from From the Old French 'male,' a bag or wallet — the same word that gives us 'mailbag.' Originally 'mail' meant the pouch a courier hauled, not the messages inside it; only later did the word slide from the container to its contents. (Note: this is unrelated to 'mail' meaning armor, which comes from Latin 'macula,' a mesh or spot.)