Chestnut是“栗子”。Old chestnut是什么意思呢？请看对话：

    A: I was doing some overtime at the office last night and missed that weekly talk show program. Anything new?

    B: You have nothing to regret. The new comedian was not very funny. He took too long to tell his jokes and they were all old chestnuts that I heard at least a dozen times before.

    Note: An old chestnut usually refers to a story that has been told repeatedly before, or a “venerable” joke. Hence, in extended use, it means anything trite, stale, or too often repeated. The origin goes back to a near-forgotten melodrama by William Diamond. The play, first produced in 1816, has one of the characters forever repeating the same joke, albeit with minor changes. The joke concerns a cork tree. On one occasion another character, Pablo, fed up with the same joke, says, “A chestnut. I have heard you tell the joke 27 times and I’m sure it was a chestnut!”