Aristos comes from Greek and means 'best' or 'most excellent,' from the root seen in aristocracy.
Aristos derives from the ancient Greek "aristos" (ἄριστος), meaning "the best" or "most excellent" — the superlative form of "agathos" (good). It is the root embedded in some of the most consequential words in Western intellectual and political history: Aristotle (aristos + telos, "the best purpose"), aristocracy (rule by the best-born), and aristeia, the Homeric tradition of heroic excellence in battle. In the Iliad, aristeia passages describe warriors at the peak of their powers — Diomedes, Achilles, Patroclus — and the word carried a nearly sacred weight in describing human beings at their highest potential.
As a given name, Aristos has been used in Greece across the centuries, often as a shortened familiar form of longer compounds like Aristophanes ("the one who shines with excellence"), Aristarchus, or Aristides. The 5th-century BCE Athenian statesman Aristides "the Just" was so admired for his fairness that his name became a byword for integrity. As a standalone name, Aristos retained currency in the Greek-speaking world precisely because of its unambiguous meaning — no metaphor required.
Today, Aristos is most common in Greece and Cyprus, with a warmth and informality in daily use that belies its grand etymological heritage. It has also surfaced in diaspora Greek communities in Australia, the US, and the UK, where parents appreciate its classical roots and the gentle challenge it poses: a child named "the best" is handed both a gift and a responsibility. The name carries no pretension in modern Greek — it is simply a name, worn lightly, that happens to contain the whole vocabulary of excellence.