The name of the symbol &, which means 'and'. It is only the name of the mark — when you read a sentence out loud you say 'and', not 'ampersand'. You mostly meet & in names of companies and pairs that belong together: 'AT&T', 'Marks & Spencer', 'Johnson & Johnson', 'rock & roll', 'terms & conditions'. It is common in logos, shop signs, titles, and short notes, and also in computer code, where it can mean something quite different from 'and'. In normal writing — an essay, a letter, an email — teachers and editors want you to write the word 'and'. Using & there looks like you were in a hurry. Two useful details, though. First, some people feel a difference between the two: 'Smith and Jones' can sound like two people who happened to work together, while 'Smith & Jones' sounds like one firm, one unit, one name. Film and TV writers actually use this on purpose. Second, the word 'ampersand' itself is a printing and design word. Ordinary people point at it and say 'the and sign'; designers, typists, and programmers say 'ampersand'. So knowing the word marks you as someone who works with text.

「&」符號；中文一般就說「and 的符號」或「&符號」。排版、設計圈子會講「連字符號」，但要注意這個說法容易和 hyphen（-）搞混，所以口語裡直接說「& 這個記號」最不會誤會。