squirrel cage

名词noun

1. 1A circular cage for a squirrel or other small animal, which rotates vertically as the animal runs at the bottom.
2. 2figuratively, by extensionA tedious, repetitive, unfulfilling activity or situation, especially one in which no progress is achieved.
3. 3(engineering) Any other device, such as a fan or rotor, that resembles a squirrel cage in form.