Where does the name "Alewife" come from? Well, it's a fish. The alewife is native to the Mystic River, which branches off in Arlington into the Alewife Brook (giving the MBTA station its name).
Legend has it that the fish was named for its large belly. Apparently, it evokes the physical form of an alehouse owner.
Wesley Ray Thomas has been entertaining commuters for the past 25 years — he's the man singing an aria by Alewife's escalator.