the.com/hobby

means An activity you do regularly for pleasure in your free time, not for money.

from Traces back to 'hobby horse' — originally a small or spirited horse, and later a wicker or stick toy horse children rode in play. By the 18th century 'hobby horse' had stretched to mean any favorite pastime someone was obsessively devoted to, as if riding it in circles for fun. 'Hobby' got clipped from that phrase and kept the sense of a pursuit you ride for pleasure rather than necessity.