Billy

Proper noun

1. A diminutive of the male given name William.
   • “By the way,” Jessamy went on, “what’s your other name? You never told me.” “Stubbs,” said Billy, “William Stubbs!”. - 1967, Barbara Sleigh, Jessamy, Sevenoaks, Kent: Bloomsbury, published 1993, →ISBN, page 98:
   • Then there’s Billy Long, a former auctioneer and Republican congressman who Trump nominated and was confirmed less than two months ago to head the Internal Revenue Service, with “little background in tax policy beyond...
2. The B-25 twin-engine bomber aircraft used during World War Two, commonly called the "B-25 Mitchell" in honor of U.S. Army General William "Billy" Mitchell.
   • Just then a squadron of "Billys" -- twin-engined B-25 Mitchell land-based bombers -- flew overhead …. - 2003 Bradley, James Flyboys. New York: Little, Brown and Company. Ch 7