As a lawyer and a dev this is pretty interesting. There's less distance between law and coding than a lot of people think. Both are expressing logic.

I agree with the comments below that you should read any contract that applies to you. Chances are that you'll understand it and this is extremely important before signing.

With that said, lawyers spend years learning how to draft and interpret contracts and I thin it's simplistic to say that it's similar to a BDD spec. There's a lot more going on under the hood.

Either way, never accept blindly and you're within your rights to seek a plain-English clarification.