What is the 'Fn Lock' key on my Samsung laptop?
They took cut out the pause break key (Really useful for devs) and the Scroll lock to reduce their cost.
And, besides, I Do Not even see a use of the 'Fn Lock' key.
So, I was really mad that: why can't they just replace the 'Fn Lock' key as it does nothing and replace it with 'Pause Break'.
So what purpose does the 'Fn lock' key serve? What does it do? If you know, please tell me, thanks.

I have the {Fn} key also on my Sony Vaio.

I (think) it's the find key. Helpful when you want to find a specify word or phrase-

It is some kind of function key. It usually marked different from the other keys, either with using a different color (on my ASUS) or with making the label of the key different (the letters inside a rectangle on my HP). You will find other of those differently marked labels all over the keys of your keyboard. If you press those keys together with the Fn-key (the same way you would do with Ctrl or Alt) you will get the function printed on the label. This way I have, on the limited space of my laptop keyboard, a Numpad, keys for regulating the brightness and the volume and the keys you miss, like break.
Just look around on your keyboard what you have, or just read the manual, it should be explained in there.