Freemason Look up Freemason at Dictionary.com
1376, originally a traveling guild of masons with a secret code; in the early 17c. they began accepting honorary members and teaching them the secrets and lore, which by 1717 had developed into the fraternity of Free and Accepted Masons. The exact origin of the free- is a subject of dispute. Some see a corruption of Fr. frère "brother," from frèremaçon "brother mason;" others say it was because the masons worked on "free" standing stones; still others see them as "free" from the control of local guilds.
mason Look up mason at Dictionary.com
c.1200, from O.Fr. masson (O.N.Fr. machun), probably from Frank. *makjo (cf. O.H.G. steinmezzo "stone mason," related to mahhon "to make;" see make (v.)). But it also may be from, or influenced by, M.L. machio, matio (7c.) which is said by Isidore to be derived from machina (see machine). The word also may be from the root of L. maceria "wall." Meaning "a Freemason" is attested from early 15c. in Anglo-Fr. Masonry "stonework" is attested from mid-14c.