BFT VS Bitcoin PoW VS PBFT
BFT is short for Byzantine Fault Tolerance. Any algorithm that can tolerate Byzantine faults is called Byzantine fault tolerant.
Byzantine faults are faults that are malicious (lying, deliberatly delaying honest nodes, etc). So if you have an algorithm that can tolerate these faults, it is called a BFT (byzantine fault tolerant). But not just that, any BFT algorithm (PoW, PoS , PBFT) solves the byzantine general's problem with some assumptions.
PBFT was the first practical BFT algorithm that can be used.
BFT relates to PoW in that PoW is also a BFT algorithm, because the Bitcoin network can contain malicious nodes that cannot be trusted, nonetheless, we can solve the byzantine generals' problem by PoW.