Webster's Revised Unabridged Dictionary · 1913

Bump

Bump (bump; 215) , transitive verb

[Compare Welsh pwmp round mass, pwmpiaw to thump, bang, and English bum, v. i., boom to roar.]

To strike, as with or against anything large or solid; to thump; as, to bump the head against a wall.

Bump , intransitive verb

To come in violent contact with something; to thump.
Bumping and jumping. — Southey

Bump ({not transcribed}) , noun

[From Bump to strike, to thump.]

1.
A thump; a heavy blow.
2.
A swelling or prominence, resulting from a bump or blow; a protuberance.
It had upon its brow A bump as big as a young cockerel's stone. — Shakespeare
3.
(Phrenology) One of the protuberances on the cranium which are associated with distinct faculties or affections of the mind; as, the bump of “veneration;” the bump of “acquisitiveness.” [Colloquial]
4.
The act of striking the stern of the boat in advance with the prow of the boat following. [English]

Bump , intransitive verb

[See Boom to roar.]

To make a loud, heavy, or hollow noise, as the bittern; to boom.
As a bittern bumps within a reed. — Dryden

Bump , noun

The noise made by the bittern.