An &mut ?

When I read terms like \&\\ and \&mut\\, I read those aloud to myself as \immutable reference\ and \mutable reference\. However, in various books and blogs, I often see the phrase \an\ \&mut\\, implying that the author is thinking something like \an ampersand\ or something. What word starting with a vowel are people thinking, when they write \an\ \&mut\\. ?