Who can tell me , What is BATNA ?

Dear Mohamed It stands for Best Alternative To Negotiating Agreement.
You may read a really nice book with the title "Getting to Yes"(if i remember well!!) which refers to this term.

Dear Mohammed, BATNA (Best Alternative to Negotiating Agreement) means, in plain business, what happens if you cannot reach an agreement during a negotiation, thus failing in closing a specific lead.
This is also a key component in your negotiation strategy and preparation.
Once you have identified what your BATNA is, you would not accept conditions to the negotiation that lead you to a situation worse than your BATNA.
Just a classical example to illustrate the BATNA: you buy a new car and the dealer is ready to buy back your old car for, say, $5'000.
You may still want to try selling the car on your own, trying to make more revenue than the dealer's offer, wouldn't you.
What is your BATNA? $5'000, less, more? Your decision, but you would know, prior to negotiating the price with a potential buyer, what is your limit.
In this example, you may want to define your BATNA as $6000, because you would go through the costs and headaches of selling the car to an unknown person.
And what if your brother offers to buy your old car for $4500, would you accept because he is your brother? The same applies to every well-prepared negotiation Hope this helps, Bernard