The quadrans (literally meaning "a quarter") or teruncius ("three unciae") was a low-value Roman bronzecoin worth one quarter of an as. The quadrans was issued from the beginning of cast bronze coins during the Roman Republic with three pellets representing three unciae as a mark of value. The obverse type, after some early variations, featured the bust of Hercules, while the reverse featured the prow of a galley. Coins with the same value were issued from other cities in Central Italy, using a cast process.
After ca. 90 BC, when bronze coinage was reduced to the semuncial standard, the quadrans became the lowest-valued coin in production. It was produced sporadically until the time of Antoninus Pius (AD 138–161). Unlike other coins during the Roman Empire, the quadrans rarely bore the image of the emperor.