(Lat. pertica), a long staff or pole frequently used in measuring land) is used, like the word pole, as a denomination both of lineal and superficial measure. As a measure of length, it is equal to 5½ yards, or 16½ feet; in square measure, the perch is the ¼th part of a rood, or equal to 30¼ square yards. (See Weights and Measures.)