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)
• 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)
• part meronym
• direct hypernym / inherited hypernym / sister term