The name "Billie" is a familiar way of saying "Bill". Many names use this technique. Johnny for John and Jacky or Jackie for Jack are examples.In turn, the name Bill is a variation of Will. Both are...
Billie Joe Armstrong's Name is actually Billie Joe Armstrong. His Mother named him. They grew up in Kentucky, Hence the name BILLIE JOE! He admits this on an interview that was posted on YouTube.