The dot appearing by itself in an expression such as
(item1 item2 . tail)
means that tail represents a list of objects at the end of a list. For example,
(A B C . (D E F))
is notationally equivalent to:
(A B C D E F)
Although dot is a valid constituent character in a symbol, no standardized symbols contain the character dot, so a period that follows a reference to a symbol at the end of a sentence in this document should always be interpreted as a period and never as part of the symbol's name. For example, within this document, a sentence such as ``This sample sentence refers to the symbol car.'' refers to a symbol whose name is "CAR" (with three letters), and never to a four-letter symbol "CAR."