1284, "shackle fixed on the foot of a horse or other beast," from O.Fr. pasturon,
dim. of pasture
"shackle for a horse in pasture," from V.L. *pastoria,
noun use of fem. of L. pastorius
"of herdsmen," from pastor
"shepherd" (see pastor
). Metathesis of -r-
and following vowel occurred 1500s. Sense extended (1530) to part of the leg to which the tether was attached.