An Etymological Dictionary of Astronomy and Astrophysics

The component of a → planispheric astrolabe that is inserted in the back of the → mater. The pin enables the main parts of the instrument (the → alidade, the → rete, and the → rule) to rotate freely around the common center of the mater and the → tympanum (online museo galileo, VirtualMuseum).

Etymology (EN): M.E. pinne, from O.E. pinn “peg, bolt,” from L. pinna “a feather, plume.”

Etymology (PE): Âsé, → axis.