Altair is a vertex of the Summer Triangle. It is an "The" type or white star located 17 light years away from Earth, one of the closest stars visible to the naked eye.

The name "Altair" is Arabic for "the flyer", from the phrase نسر الطائر an-nasr aţ-ţā?ir "a flight eagle". The spelling "Atair" is also used frequently.

Altair is most notable for its extremely rapid rotation; by measuring the width of its spectral lines, it was determined that its equator does a complete rotation in about 6 1/2 hours (various other sources give 9 hours, or 10.4 hours). In comparison, our star, the Sun, requires a little more than 25 days for a complete rotation. As a result of its rapid rotation, Altair is oblate: its equatorial diameter is at least 14 percent greater than its polar diameter.

Altair, along with Beta Aquilae and Gamma Aquilae, form the well-known line of stars sometimes referred to as the shaft of Aquila.