informal

a subject, idea, or joke which has been discussed or repeated so many times that it is not interesting or funny any more.

I wondered whether there might, after all, be some truth in the old chestnut that one's school days are the happiest of one's life.

Play allows us to rediscover the child in ourselves - that old chestnut.

• the bandwagon effect
• the bane of life
• the bane of your life
• the bare bones
• the battle lines are drawn
• the battle of the sexes
• the be-all and end-all
• the beau monde
• the beauty of
• the beauty of something
• the beginning of the end
• the best of both worlds
• the best of the best
• the best of the lot
• the best thing since sliced bread
• the better part of
• the better part of something
• the Bible Belt
• the big daddy
• the bigger they are, the harder they fall.
• the big picture
• the big smoke
• the big time
• the bird has flown.
• the birds and the bees