Byzantine Fault Tolerance
A classic computer science problem in dealing with distributed consensus. A problem/situation of trying to achieve consensus in a decentralized network that possibly contains unreliable or malicious actors. Because (some) blockchains do not require trust between users, they are tasked with solving this coordination problem. The name comes from a hypothetical battle in which two Byzantine generals must attack the same enemy city from either side at the same time to achieve victory; however, coordination between the generals might be hampered by unreliable messengers or actions in bad faith by one of the generals.