1. [n]  an auxiliary activity
2. [n]  small Old World falcon formerly trained and flown at small birds
3. [n]  a child's plaything consisting of an imitation horsehead on one end of a stick; the child straddles it and pretends to ride

Hobby
Part two of a trilogy about the childhood and adolescence of Merlin the magician. After dreaming he is a bird with flame red feathers, Merlin awakens to discover that his house is engulfed in fire and his adoptive family is dead. He soon takes up with a band of traveling performers who name him Hobby and exploit his talents for dreaming the future.

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1. \Hob"by\, n.; pl. {Hobbies}. [OE. hobi; cf. OF. hobe,
   hob['e], F. hobereau a hobby, a species of falcon. OF. hober
   to move, stir. Cf. {Hobby} a horse.] (Zo["o]l.)
   A small, strong-winged European falcon ({Falco subbuteo}),
   formerly trained for hawking.
   

2. \Hob"by\, Hobbyhorse \Hob"by*horse`\, n. [OE. hobin a nag,
   OF. hobin hobby; cf. hober to stir, move; prob. of German or
   Scand. origin; cf. Dan. hoppe a mare, dial. Sw. hoppa; perh.
   akin to E. 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. [ Usually under the form
      {hobbyhorse}.]
   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.
      [Usually under the form {hobby}.]
            Not one of them has any hobbyhorse, to use the
            phrase of Sterne.                     --Macaulay.