The Collaborative International Dictionary of English v.0.48:
Bombilation \Bom`bi*la"tion\, n. A humming sound; a booming. [1913 Webster] To . . . silence the bombilation of guns. --Sir T. Browne. [1913 Webster]WordNet (r) 3.0 (2006):
bombilation n 1: sound of rapid vibration; "the buzz of a bumble bee" [syn: buzz, bombilation, bombination]