Assets\Charactershoot.cs(6,12): error CS0246: The type or namespace name 'Gun' could not be found (are you missing a using directive or an assembly referen

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class charactershoot : MonoBehaviour {
    public Gun gun;

    public int shootButton;
    public KeyCode reloadKey;

    void Update() {
        if(Input.GetButtonDown("Fire1")) {
            Gun.Shoot();
        }

        if(Input.GetKeyDown("r")) {
            Gun.Reload();
        }
    }
}

Is “gun” a GameObject?