The Stellar white paper "presents federated Byzantine agreement (FBA), a model suitable for worldwide consensus." It then goes on to state that it "further presents the Stellar consensus protocol (SCP), a construction for FBA." When reading the paper, I fail to identify the point at which it is no longer FBA that is described but SCP. My interpretation of the wording is that FBA is part of SCP but not all that is SCP is FBA. So -- what differentiates the two terms? Where to draw the line?
The Stellar Consensus Protocol is a type of federated Byzantine agreement protocol. So FBA is a broader category that includes SCP.
"Stellar introduces a new Byzantine agreement protocol, SCP (Stellar Consensus Protocol), through which token issuers designate specific validator servers to enforce transaction finality."