The symbol & has an interesting history. It is a modified form of a ligature (combined character) for the Latin word "et," meaning "and." At one time & was treated as the 27th character in the English alphabet, following z. Webster's Word Histories explains that in late medieval England, spelling was managed syllable by syllable, with spaces between each break. Consequently, when one of the four single-character English words (a, I, o, and &) appeared in a sentence, the writer would clarify that the letter was the whole word rather than the first syllable of a longer word by adding "per se" after the character's first appearance and then repeating the character. The Latin phrase "per se" means "by, of, or in itself." Thus the sentence

"Open, o sweet iris, and I shall see a throne an aphid might call his heavenly home."

would have been rendered as

"O pen, o per se, o sweet i ris, & per se, & I per se, I shall see a per se, a throne an a phid might call his heav en ly home."

Though the "per se" gloss dropped out of English usage with the crossover from syllabic spelling to whole-word spelling, the past is vaguely remembered in the spelling of the character &: "ampersand."