The story
Two different origins: * The place in Bedfordshire is recorded in 1196 as Billendon, from the Old English personal name *Billa + -ing (“belonging to”) + dūn (“hill”). * The village in Lancashire is probably named with *billing (“sword-shaped, ridge-shaped”) (see bill) + dūn (“hill”).
Etymology from Wiktionary, CC BY-SA 4.0.