p. pr. & vb. n. - of Boom
a. - Rushing with violence; swelling with a hollow sound; making a hollow sound or note; roaring; resounding.
a. - Advancing or increasing amid noisy excitement; as, booming prices; booming popularity.
n. - The act of producing a hollow or roaring sound; a violent rushing with heavy roar; as, the booming of the sea; a deep, hollow sound; as, the booming of bitterns.