"It would have been confusing to say “X, Y, Z, and.” So, the students said, “and per se and.” Per se means “by itself,” so the students were essentially saying, “X, Y, Z, and by itself and.” The term per se was used to denote letters that also doubled as words, such as the letter I (for “me”) and A. By saying “per se,” you clarified that you meant the symbol and not the word.
Over time, “and per se and” was slurred together into the word we use today: ampersand."
Over time, “and per se and” was slurred together into the word we use today: ampersand."