'Plethrum' definitions:

Definition of 'Plethrum'

From: GCIDE
  • Plethron \Pleth"ron\, Plethrum \Pleth"rum\, n.; pl. Plethra. [NL., fr. Gr. ?.] (Gr. Antiq.) A long measure of 100 Greek, or 101 English, feet; also, a square measure of 10,000 Greek feet. [1913 Webster]