• WordNet 3.6
    • n hobbyhorse a child's plaything consisting of an imitation horse mounted on rockers; the child straddles it and pretends to ride
    • n hobbyhorse a topic to which one constantly reverts "don't get him started on his hobbyhorse"
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Webster's Revised Unabridged Dictionary
    • Hobbyhorse A stick, often with the head or figure of a horse, on which boys make believe to ride.
    • Hobbyhorse A strong, active horse, of a middle size, said to have been originally from Ireland; an ambling nag.
    • Hobbyhorse 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."
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Webster's Revised Unabridged Dictionary
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


In literature:

The country has paid dear for Sir John's hobbyhorse.
"More Letters of Charles Darwin" by Charles Darwin
The gas we had on the Toft's hobbyhorses.
"Ulysses" by James Joyce
Not one of them has any hobbyhorse, to use the phrase of Sterne.
"The Diary and Letters of Madame D'Arblay, Vol. 1 (of 3)" by Fanny Burney
You know how pleased a boy is when his hobbyhorse creaks.
"Dew Drops, Vol. 37, No. 8, February 22, 1914" by Various
While he went within doors he had left the hobbyhorse in the snow, close to the wall; and he came back there to wait.
"Christmas" by Zona Gale
Nobody could have remained in a normal seat on such terrain, but Bordman felt hopelessly undignified riding what amounted to a hobbyhorse.
"Sand Doom" by William Fitzgerald Jenkins
Not one of them has any hobbyhorse, to use the phrase of Sterne.
"Critical and Historical Essays, Volume III (of 3)" by Thomas Babington Macaulay
But Lady M. tall brown old party with nose like hobbyhorse.
"The Princess Virginia" by C. N. Williamson
Not one of them has any hobbyhorse, to use the phrase of Sterne.
"Woman's Work in English Fiction" by Clara Helen Whitmore
He'd drive a hobbyhorse into hysterics.
"What Will People Say?" by Rupert Hughes