Original: Sichuan pepper (or Szechuan pepper) is the outer pod of the tiny fruit of a number of species in the genus Zanthoxylum (most commonly Z. piperitum, Z. simulans, and Z. schinifolium), widely grown and consumed in Asia as a spice.
Simplified: Most commonly these plants are Z. piperitum, Z. simulans, Z. sancho or Z. schinifolium.