airbag

1. (automotive) A protective system in automobiles in which when a crash occurs, a bag containing nitrogen, formed by the explosive decomposition of sodium azide, quickly inflates in front of the driver or passenger, preventing injury to the head. Side air bags, including the back seat passengers, also prevent injury.Examples: "In a fast German car / I'm amazed that I survived / An airbag saved my life"; "However, the challenges for the railway world are much greater than for automotive as we generally have more occupants, higher speeds, greater masses, higher energies, and an absence of seatbelts or airbags to contend with."

2. (slang) A person who talks too much; a windbag or gossip.slang