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
an arithmetic operation that is the inverse of division; the product of two numbers is computed; "the multiplication of four by three gives twelve"; "four times three equals twelve"
a multiplicative increase; "repeated copying leads to a multiplication of errors"; "this multiplication of cells is a natural correlate of growth"
(American football) a play in which a defensive player is allowed to cross the line of scrimmage and then blocked off as the runner goes through the place the lineman vacated