An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

In a → planispheric astrolabe, a vane on an end of an → alidade with a hole, slot, or other indicator through which one can view a distant object. There may also be a pointer or pointers on the alidade to indicate a position on a scale.

Diminutive of L. pinna "feather, wing, fin;" + → -ule.

Mori (Biruni).