Arguments

item  any value or expression

Return

T if  is an atomic element, NIL otherwise

Example

(setq x '(1 2 3))
(1 2 3)
(atom '(1 2 3))  nil
(setq y 'x)
X
(atom 'x)  T
(atom 'y)  T
(atom x)  nil
(atom y)  T
(atom 12.34)  T
(atom "xyz")  T
(atom PI)  T
(atom (entlast))  T
(atom T)  T
(atom NIL)  T

Remarks

effectively, any  which is not a List or DottedPair, is an "atomic" value