GameObject.layer
var layer: int;
int layer;
layer as int
Description

The layer the game object is in. A layer is in the range [0...31].

Layers can be used for selective rendering from cameras or ignoring raycasts.
	// Put the game object in the ignore raycast layer
	gameObject.layer = 2;
using UnityEngine;
using System.Collections;

public class Example : MonoBehaviour {
    void Example() {
        gameObject.layer = 2;
    }
}
import UnityEngine
import System.Collections

public class Example(MonoBehaviour):

	def Example() as void:
		gameObject.layer = 2