Android XPath index issue

Very new to Android Testing.<br/>
I came across this Xpath

xpath: (//android.widget.ImageView[1])[3]

I know that in ImageView1 "1" is the index of the element.<br/>
What is [3] here???

Update:<br/>

I am running a test (mobile App). The above XPath is to tap on the Bell icon.<br/>
It did tap on the bell icon perfectly.<br/>
But today when I run my test it doesn't tap on the Bell icon instead it taps on the user Profile Picture.

Using appium I found the xpath of the Bell icon as below:

xpath: /hierarchy/android.widget.FrameLayout/android.widget.LinearLayout/android.widget.FrameLayout/android.widget.LinearLayout/android.widget.FrameLayout/android.widget.FrameLayout/android.view.ViewGroup/android.view.ViewGroup/android.view.ViewGroup[1]/android.view.ViewGroup/android.view.ViewGroup/android.view.ViewGroup/android.view.ViewGroup/android.view.ViewGroup[2]/android.view.ViewGroup[1]/android.view.ViewGroup[2]/android.view.ViewGroup/android.widget.ImageView

Now when I use this new xpath the Bell icon is clicked.

Are both the Xpaths same?? <br/>
Why is this new xpath so long? is there a way to shorten this??<br/>
Any kind of help is really Appreciated!!!

The expression //android.widget.ImageView[1] selects every android.widget.ImageView that is the first child of its parent. This will in general select a set of nodes. The [3] selects the third node in this set.

Try to access bell button using class name.

(//*[@class="Class name"])[2]

  (//*[@class="android.widget.ImageView"])[2]

You are getting the absolute xpath using the appium(which you have stated above) and the one you are using like //android.widget.ImageView1)[3] is the relative xpath of the icon.

Absolute xpath : It is the path from the root element to the particular element.
Relative xpath : It is the reference path of the element or particular path to the element.