NDA means Non disclosure Agreement
An NDA is a confidentiality statement, which says so much that the two people/companies that sign the contract agree that they keep the information or products it is about for themselves. Suppose someone has created a particular product and wants to test how it is among a number of people. These then all close an NDA with the creator of the product, so that not other people come to know about it. An NDA guarantees the intellectual property of the client, and often there is also an extremely high fine on non-compliance with the NDA.