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 silver-white metallic element of the platinum group that resembles platinum; occurs in some copper and nickel ores; does not tarnish at ordinary temperatures and is used (alloyed with gold) in jewelry
a score in American football; a player is tackled behind his own goal line
a safe place; "He ran to safety"
the state of being certain that adverse effects will not be caused by some agent under defined conditions; "insure the safety of the children"; "the reciprocal of safety is risk"