The tetartemorion was an ancient Greek coin that represented one-quarter of an obol, a principal currency unit in many Greek city-states. The name tetartemorion derives from the Greek word tetartos, meaning “quarter,” and moria, meaning “part,” signifying that it was worth one-fourth of the obol, which itself was one-sixth of a drachm. The tetartemorion was a small and low-value coin, used for everyday transactions, particularly in the context of small-scale trade or purchases.