Everything except the first element of a list is the cdr of the list. The quote function inhibits the evaluation of its argument. It returns its argument literally. You can create any list with cons.
Predicates return nil for false.
The atom t means true, and evaluates to itself. Predicates may return t for true, or they may return any other non-nil value. If initial-name is not used, it is not evaluated. The macro defvar only has an effect the first time it is called on a symbol. Documentation may be provided as a string.