(dating) A prescheduled phone call to another person who knows where one is and who one was going out with. A missed check-in (or using a pre-arranged code phrase for danger) signals one's contact person to call for help.

Any coffin specially designed for the occupant to leave it in case of premature burial, such as by warning other people to help him.

plural of safety coffin

Safety when using the Internet.

(architecture) An arch built in the body of a wall to relieve the pressure, as over a door or window.

A plug of soft metal in an opening in a steam boiler, designed to melt when the temperature rises to a certain point, and thus allow the escape of steam.

plural of safety plug

plural of safety arch

plural of safety stop

A waterproof woven tube enclosing a flammable substance which burns at a regular rate.