| air bag |
a bag in the front of some cars that blows up with air instantly in a crash to stop the passengers from being thrown forward. |
| air conditioner |
a machine that cools the air in a room or car. An air conditioner also takes the dust and dampness out of the air. |
| air conditioning |
a system that cools air and takes dust and dampness out of it. Air conditioning is used inside buildings and cars. |
| air force |
the branch of a nation's armed forces that trains and fights using aircraft. |
| air pressure |
the force of air on things. Air pressure has to do with how much force air has when it has been compressed into a space like a tire. It is also the pressure of the earth's atmosphere. |
| into thin air |
out of sight. |
| off the air |
not broadcast on radio or television. |
| on the air |
broadcast on radio or television. |
| up in the air |
not decided, not settled, or not certain. |