Noun

1. A fit of lunacy or madness; a period of frenzy; a crazy or unreasonable freak.

   These dangerous, unsafe lunes i' the king. Shakespeare

Noun

1. A concave figure formed by the intersection of the arcs of two circles on a plane, or on a sphere the intersection between two great semicircles.

   • 1984: What he worried about was any eventual convexity, a shrinking, it might be, of the planet itself to some palpable curvature of whatever he would be standing on, so that he would be left sticking out like a projected radius, unsheltered and reeling across the empty lunes of his tiny sphere. — Thomas Pynchon, Slow Learner

2. anything crescent-shaped

Usage notes

Noun

1. A leash for a hawk.
   • 1485, Sir Thomas Malory, Le Morte Darthur, Book VI:

     than he was ware of a faucon com over his hede fleyng towarde an hyghe elme, and longe lunes aboute her feete.