pintail

jouhisorsa A pintail duck, a type of dabbling duck with a characteristic pointed tail.
A northern pintail, Anas acuta, a dabbling duck of the northern hemisphere that has a long pointed tail.
A pin-tailed snipe, Gallinago stenura.
puhekieltä The end of a fastening pin or mandrel on a Huckbolt or pop rivet that is broken off when installation is complete.
1994, James William Fitch, Motor Truck Engineering Handbook (page 110)

The collar is placed over the fastener pintail and the installation tool is placed over the pintail. The tool pulls on the pin drawing the parts together until the collar is swaged into locking grooves.