arbitrator comes from Late Latin arbitrator ('one who judges'), from arbitrari ('to judge, decide'), from arbiter ('judge, witness'). The formation is best read through the historical forms named above, with the modern spelling preserving the outcome of that older derivational path. In modern use, the noun sense is "an impartial person chosen to settle a dispute", which keeps the etymology connected to the word's present dictionary value rather than treating it as a merely historical label. The wider word family includes related English forms such as arbitrate, arbitration, arbiter, arbitrary, showing how the same base continues to support neighboring English vocabulary. The principal historical forms in the chain include Latin arbitrator, Latin arbitrari, Latin arbiter, which anchor the explanation in named linguistic material.