Well Why Didn't You Just Say So: &

The "ampersand," a familiar keyboard symbol, represents a shortened version of a cumbersome phrase. As the phrase was first used, it was "and per se and," or more literally, "and in itself and." In a much simpler form, this just means "and." The symbol derived from the Latin word et, which means "and" — its form evolved from the two separate letters, E and T, gradually merging into a single new character.

The Word Origin Calendar

And I for one am grateful that it did. "and per se and" ... cumbersome is not the word.