Definition of potiron in US English:

potiron

noun

rare
  • A kind of pumpkin, especially one with a flattened shape and orange skin.

Origin

Mid 17th century; earliest use found in John Evelyn (1620–1706), diarist and writer. From French potiron a kind of large champignon, a kind of pumpkin, of uncertain origin, perhaps (via medical usage) from post-biblical Hebrew piṭriyyāh mushrom.