Poll = head, as in head count. This tax was imposed on three occasions in the last quarter of the 14c. The first was that of 1377; this was followed in 1379 by a graduated tax. The latter's failure resulted in the removal of the *chancellor, Richard Scrope. In 1380, parliament permitted a further tax through the new chancellor, Simon Sudbury, archbishop of Canterbury. The tax was assessed as three groats on every man and woman over the age of 15. Its consequence at both times — 1379 and 1380 — was civil unrest, though the *Peasants' Revolt of 1381 was more serious, esp. in the loss of life.
Dictionary of Medieval Terms and Phrases. Christopher Coredon with Ann Williams.