Same entry in Photius (pi778 Theodoridis), similar in other lexica (and Pollux 1.77-78).
According to LSJ, the headword, a neuter noun, is later Greek for peri/stulon (the noun used in the present gloss). Moeris the Atticist says peristw=|on (sic: so accented) is Attic, while peri/stulon is common Greek (koine); but the earliest writers (outside lexicography) to use peri/stw|on are Josephus and Cassius Dio.