A forward is just a future that isn't standardized and not traded on an exchange. Forwards are over the counter contracts that are written for each deal.
Forwards came first. You would go to an investment bank tell them you wanted to hedge whatever you had and they would write up the contract between you and them. Obviously there is no secondary market for these things and two contracts could have different terms in them.
So futures were invented. They standardized the underlying product (e.g. a type of wheat, a particular duration on bonds, a fineness of metal, etc), the expiration date, the delivery location (or financially settled), and the size. Now since all these contracts are fungible a market can be formed to trade them back and forth.
I understand the terminology difference of forwards and futures, what I was asking about was when does a deal become a forward? The standard "I'll agree to buy oil from you at this price next year" is obviously a forward, but a deal where there may be no particular timeline or even a promise of one seems to be more hazy.
The dividing line would be the requirement for all contracts to be equivalent and traded on a venue. So an expiration date is probably a requirement. I have a hard time imagining such an open ended contract.
Forwards came first. You would go to an investment bank tell them you wanted to hedge whatever you had and they would write up the contract between you and them. Obviously there is no secondary market for these things and two contracts could have different terms in them.
So futures were invented. They standardized the underlying product (e.g. a type of wheat, a particular duration on bonds, a fineness of metal, etc), the expiration date, the delivery location (or financially settled), and the size. Now since all these contracts are fungible a market can be formed to trade them back and forth.
Those are basically the only differences.