Ampersands

The word ampersand is a conflation of the phrase "and per se and", meaning "and by itself and". The Scots and Scottish English name for & is epershand, derived from "et per se and", with the same meaning.
Traditionally, in English-speaking schools when reciting the alphabet, any letter that could also be used as a word in itself ("A," "I," and, at one point, "O") was preceded by the Latin expression "per se" (Latin for "by itself"). Also, it was common practice to add at the end of the alphabet the "&" sign, pronounced "and". Thus, the recitation of the alphabet would end in: "X, Y, Z and per se and." This last phrase was routinely slurred to "ampersand" and the term crept into common English usage by around 1837.
Through folk etymology, it has been claimed that André-Marie Ampère used the symbol in his widely read publications, and that people began calling the new shape "Ampere's and".

The ampersand can be traced back to the 1st century A.D. and the Old Roman cursive, in which the letters E and T occasionally were written together to form a ligature. In the later and more flowing New Roman Cursive, ligatures of all kinds were extremely common; figure 2 and 3 from the middle of 4th century are both examples of how the et-ligature could look in this script. However, during the following development of the Latin script that led up to the Carolingian minuscule (9th century), while the use of ligatures in general diminished, the et-ligature continued to be used and gradually became more stylized and less revealing of its origin (figures 4–6).
The modern italic type ampersand is a kind of et-ligature that goes back to the cursive scripts developed during the Renaissance. After the advent of printing in Europe in 1455, printers made extensive use of both the italic and Roman ampersands. Since the ampersand's roots go back to Roman times, many languages that use a variation of the Latin alphabet make use of it.
The ampersand often appeared as a letter at the end of the Latin alphabet, as for example in Byrhtferð list of letters from 1011. Similarly, & was regarded as the 27th letter of the English alphabet, as used by children (in the USA). An example may be seen in M. B. Moore's 1863 book The Dixie Primer, for the Little Folks. In her 1859 novel Adam Bede, George Eliot refers to this when she makes Jacob Storey say, "He thought it had only been put to finish off th' alphabet like; though ampusand would ha' done as well, for what he could see."
The ampersand should not be confused with the Tironian "et", which is a symbol similar to the numeral 7. Both symbols have their roots in the classical antiquity, and both signs were used up through the Middle Ages as a representation for the Latin word "et" ("and"). However, while the ampersand was in origin a common ligature in the everyday script, the Tironian "et" was part of a highly specialised stenographic shorthand.

The ampersand is now rarely used when writing paragraphs. The main surviving use of the ampersand is in the formal names of businesses (especially firms and partnerships, particularly law firms, architectural firms, and stockbroker firms). When the ampersand forms part of a registered name (e.g. Brown & Watson), it should not be replaced with and.
With the growth of mobile phone usage and text messaging, the ampersand is gaining new use in SMS language both as a representation for the word "and" and in rebus form, such as "pl&" in place of the word "planned".
The ampersand is also often used when addressing an envelope to a couple: "Mr. & Mrs. Smith" or "John & Jane".
The ampersand is also used for book and movie titles, such as Harry & Tonto, as well, and in some other proper names. In these cases, & is interchangeable with the word and; the distinction between them is mostly aesthetic. However, in film credits for story, screenplay, etc., & indicates a closer collaboration than and. The ampersand is used by the Writers Guild of America to denote when two writers collaborated on a specific script, rather than rewrote another writer's work. In screenplays, two authors joined with & collaborated on the script, while two authors joined with and worked on the script at different times and may not have consulted each other at all.[10] In the latter case, they both contributed enough significant material to the screenplay to receive credit but did not work together (more than likely one was hired to rewrite the previous writer's script).
Many of the first role-playing games used the & in their titles along with alliteration: Tunnels & Trolls, Bunnies & Burrows, and most famously Dungeons & Dragons, which is commonly abbreviated as D&D.
In APA style the ampersand is used when citing sources in text such as (Jones & Jones, 2005).
The phrase et cetera ("and so forth"), usually written as etc. can be abbreviated &c. representing the combination et + c(etera).
The ampersand can be used to indicate that the "and" in a listed item is a part of the item's name and not a separator (e.g. "Rock, pop, rhythm & blues, and hip hop").