The name for the ampersand character is a contraction of the phrase "and per se and," according to one of the Childcraft books I used to have. This meant "&, standing by itself, means ‘and’" and used to be recited by school children with the letters of the alphabet.

The Take Our Word For It newsletter #10 at says that the symbol "was invented in 63 BC by {a Roman named} Marcus Tirus" as a shorthand for "et." Learning Kingdom and have the guy's name as "Tiro" but the same date.