Hobby
Hobby , noun
[Old English hobi; compare Old French hobe, hobé, French hobereau a hobby, a species of falcon. Old French hober to move, stir. Compare Hobby a horse.]
(Zoology) A small, strong-winged European falcon (Falco subbuteo), formerly trained for hawking.
Hobby , noun
[Old English hobin a nag, Old French hobin hobby; compare hober to stir, move; prob. of German or Scand. origin; compare Danish hoppe a mare, dial. Swedish hoppa; perh. akin to English hop to jump.]
1.
A strong, active horse, of a middle size, said to have been originally from Ireland; an ambling nag. — Johnson
2.
A stick, often with the head or figure of a horse, on which boys make believe to ride.
3.
A subject or plan upon which one is constantly setting off; a favorite and ever-recurring theme of discourse, thought, or effort; that which occupies one's attention unduly, or to the weariness of others; a ruling passion.
Not one of them has any hobbyhorse, to use the phrase of Sterne.
Also: Hobbyhorse