1. the part of the foot of a horse, cow, etc., between the fetlock and the hoof.
2. either of the two bones of this part, the upper or first phalanx (great pastern bone) and the lower or second phalanx (small pastern bone)between which is a joint (pastern joint
1284, "shackle fixed on the foot of ahorse or other beast," from O.Fr.pasturon, dim. of pasture "shackle for ahorse in pasture," from V.L. *pastoria,noun use of fem. of L. pastorius "ofherdsmen," from pastor "shepherd" (seepastor). Metathesis of -r- and followingvowel occurred 1500s. Sense extended(1530) to part of the leg to which thetether was attached.
"It turned out that Miss Sato was to some degree familiar with both horses and riding equipment, and amiably set about describing the differences between the traditional Japanese saddle and those of the English and Western schools. However, when it came to details of the horses themselves, she regretfully shook her head and admitted that she knew nothing about the angle of pasterns."
- Laurie R. King, Dreaming Spies (2015)