- a person, animal, or thing that whistles
- any of various birds having a whistling call or making a whistling sound in flight, as the goldeneye
- hoary marmot
- a horse affected with whistling (sense )
- a radio wave, generated by lightning, high-energy electrons, etc. that travels along the earth's magnetic field lines and is heard as a whistling sound on radio receivers
- One that whistles: a whistler of popular tunes.
- a. A marmot (Marmota caligata) of the mountains of northwest North America, having a grayish coat and a shrill, whistling cry.b. Any of various birds that produce a whistling sound.c. A horse having a respiratory disease characterized by wheezing.
- Physics A very-low-frequency electromagnetic wave of 1 to 30 kilohertz produced by atmospheric disturbances such as lightning and having a characteristically decreasing frequency responsible for a whistling sound in detection equipment.