Noun

• S: (n) hobbyhorse (a topic to which one constantly reverts) "don't get him started on his hobbyhorse"
• direct hypernym / inherited hypernym / sister term
• S: (n) preoccupation (an idea that preoccupies the mind and holds the attention)
• direct hyponym / full hyponym
• direct hypernym / inherited hypernym / sister term
• S: (n) idea, thought (the content of cognition; the main thing you are thinking about) "it was not a good idea"; "the thought never entered my mind"
• derivationally related form
• S: (n) hobby, hobbyhorse, rocking horse (a child's plaything consisting of an imitation horse mounted on rockers; the child straddles it and pretends to ride)