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hobby : a pursuit outside one’s regular occupation engaged in especially for relaxation — Webster

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Hobby is a regular activity that is done for enjoyment, typically during one’s leisure time. Hobbies can include collecting themed items and objects, engaging in creative and artistic pursuits, playing sports, or pursuing other amusements. A list of hobbies is lengthy and always changing as interests and fashions change. By continually participating in a particular hobby, one can acquire substantial skill and knowledge in that area. Engagement in hobbies has increased since the late nineteenth century as workers have more leisure time and advancing production and technology have provided more support for leisure activities. As some hobbies have become less popular, like stamp collecting, others have been created following technological advances, like video games. — Wikipedia

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