nPlethron(Gr. Antiq) A long measure of 100 Greek, or 101 English, feet; also, a square measure of 10,000 Greek feet.
Century Dictionary and Cyclopedia
nplethronIn ancient Greece, a fundamental land-measure, being the square of 100 feet, or 10,000 square feet. As a measure of length, the plethron was the side of this square, the sixth part of a stadium, or about 101 English feet.