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 http://www.takeourword.com/Issue010.html says that the symbol "was invented in 63 BC by {a Roman named} Marcus Tirus" as a shorthand for "et." Learning Kingdom and About.com have the guy's name as "Tiro" but the same date.