Fir, an evergreen cone-bearing tree. Young firs taper to a point at the top, but older trees vary in shape. The flat, narrow leaves, or needles, of firs grow on all sides of the twigs, but are twisted so as to appear to grow in two rows. Fir cones are cylindrical, and are borne upright. The soft wood of firs, white to pale brown, is used for boxes, barrels, sashes, doors, interior construction, and papermaking. Fragrant fir leaves are used in pillows.

There are about 40 species of firs, 10 of which are native to North America. The balsam fir is found from Virginia to Newfoundland and northwestward to the Yukon. It grows from 40 to 60 feet (12–18 m) tall and is the most fragrant of all native firs. A resin called Canada balsam forms in blisters on the young bark of balsam firs. Canada balsam is used as a transparent adhesive in joining lenses and mounting objects to be studied under the microscope.

The giant fir, also called grand fir or lowland fir, grows in valleys and on low mountain slopes along the Pacific coast from northern California to southwestern British Columbia. It may reach a height of 300 feet (90 m), with a trunk about six feet (1.8 m) in diameter. The needles, nearly 2 ½ inches (64 mm) long, are dark green above and silvery-white on the undersides.

The noble fir, another large fir, grows from 100 to 200 feet (30–60 m) in height. It is found in the forests of central Oregon and Washington.

The Douglas, or red, fir is not a true fir.

Firs belong to the genus Abies of the pine family, Pinaceae. The balsam fir is A. balsamea; giant, A. grandis; noble, A. procera.