Meaning

noun an auxiliary activity

noun a child's plaything consisting of an imitation horse mounted on rockers; the child straddles it and pretends to ride

noun small Old World falcon formerly trained and flown at small birds

originShortened from hobby-horse, from Middle English hoby, hobyn, hobin (“small horse, pony”), from Old French hobi, *haubi, haubby, hobin ("a nag, hobby"; > Modern French aubin, Italian ubino), of Germanic origin: from Old French hober, ober (“to stir, move”), from Old Dutch hobben (“to toss, move up and down”); or from North Germanic origin related to Danish hoppe (“a mare”), Old Swedish hoppa (“a…

Etymology from Wiktionary, CC BY-SA 3.0