Fidget spinner
A small handheld toy with a central bearing and rotating arms, spun between the fingers for amusement or sensory stimulation.
Rolling-element bearing: A mechanical bearing that uses rolling elements, such as balls, to reduce friction between moving parts. The central bearing lets the spinner’s body rotate around a finger-held center.
Catherine Hettinger: An American inventor associated with a 1997 patent for a spinning toy design. Her patent is frequently connected to the later fidget-spinner boom, though it described a different design.
Fidgeting: Small, often repetitive movements made while sitting or concentrating. Spinning the toy is a deliberate form of hand fidgeting.
Stress ball: A squeezable ball used to provide hand exercise or tactile stimulation. A stress ball offers resistance through squeezing rather than sustained rotation.
Angular momentum: A conserved physical quantity associated with rotational motion, determined by an object's rotation and mass distribution. The spinning arms carry angular momentum that resists changes in their rotational motion.
U.S. Patent 5,685,715: A 1997 United States patent for a spinning toy invented by Catherine Hettinger. The patent documents an earlier toy concept often cited in accounts of fidget spinners.
Attention-deficit/hyperactivity disorder: A neurodevelopmental disorder characterized by persistent patterns of inattention and/or hyperactivity-impulsivity that impair functioning. The toy was marketed as a focus aid, including for people with ADHD, without strong evidence of benefit.
Fidget cube: A small handheld object with different tactile controls on its faces for repetitive manipulation. A fidget cube provides varied actions, while a spinner centers on one rotating motion.
Moment of inertia: A measure of how strongly an object's mass distribution resists angular acceleration about an axis. Arm shape and mass distribution affect how readily the spinner accelerates or slows.
Fidget spinner craze: A 2017 surge in the popularity and commercial sale of fidget spinners. The toy became a mass-market phenomenon during this brief period.