HOBBYHORSE

hobby, hobbyhorse, rocking horse

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

hobbyhorse

(noun) a topic to which one constantly reverts; “don’t get him started on his hobbyhorse”

Source: WordNet® 3.1

Noun

hobbyhorse (plural hobbyhorses)

Alternative spelling of hobby horse

Source: Wiktionary

Hob"by, Hob"by*horse`, n. Etym: [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.

Source: Webster’s Unabridged Dictionary 1913 Edition