Composition
Composition[f, g, h] represents the composition of functions, applied right to left: f[g[h[x]]].
Examples
Compose functions:
(* f[g[x]] *)
comp = Composition[Sqrt, Abs]
comp[-4]
(* 2 *)
(* Chain multiple functions *)
Composition[Length, Flatten, Table][i, {i, 3}, {j, i}]
(* 6 *)
(* Using @* operator *)
(Sqrt @* Abs)[-9]
(* 3 *)Please visit the official Wolfram Language Reference for more details.