ListQ

ListQ[expr] gives True if the head of expr is List, and False otherwise.

Examples

Test for lists:

ListQ[{1, 2, 3}]
(* True *)

ListQ[5]
(* False *)

Associations are not lists:

ListQ[<|"a" -> 1|>]
(* False *)

Please visit the official Wolfram Language Reference for more details.