The contract, approved by both parties, the Contractee (buyer) and the Contractor (seller), is then deployed (published) to the blockchain.
Deployment is the first actual blockchain transaction* that changes the contract state from draft to deployed state.
Deployed state means that the new contract is given the contract address. It is the place in the blockchain database where the contract, its data, and funds (if any) are stored.
More on the contract address, and its role in various contract operations is here.
Unlike the draft state which requires both parties' involvement, the deployed state requires a Contractee to take a single action "Deploy". At this point, the Contractor is advised not to proceed with the order.