air passage provided by a retractable device containing intake and exhaust pipes; permits a submarine to stay submerged for extended periods of time
breathing device consisting of a bent tube fitting into a swimmer's mouth and extending above the surface; allows swimmer to breathe while face down in the water
a conflict of opposed ideas or attitudes or goals; "a collision of interests"
an accident resulting from violent impact of a moving object; "three passengers were killed in the collision"; "the collision of the two ships resulted in a serious oil spill"
(physics) an brief event in which two or more bodies come together; "the collision of the particles resulted in an exchange of energy and a change of direction"