c. 1300, armurie, "arms and weapons collectively; defensive armor;" see arm (n.2) + -ory and compare Old French armeurerie, armoirie. The meaning "place where arms are manufactured" is from mid-15c. (see armor + -y (1)). Also in Middle English as "arsenal, storehouse of weapons" (mid-15c.); the sense of "science of heraldry" (late 15c.) is from Old French armoierie, from armoier "to blazon," from Latin arma "weapons" (see arm (n.2)).