British, American & Australian, American

something that you say when you want your luck or a good situation to continue.

It's been fine all week and, touch wood, it'll stay fine for the weekend.

We haven't had any problems with the car so far, knock on wood.

• the grass roots
• the graveyard shift
• the gravy train
• the greasy pole
• the great and the good
• the greatest thing since sliced bread
• the green-eyed monster
• the Grim Reaper
• the groves of academe
• the hair of the dog
• the hair of the dog that bit you
• the halcyon days
• the hand that rocks the cradle .
• the hand that rocks the cradle rules the world.
• the happy event
• the hard sell
• the hard stuff
• the head honcho
• the heart rules the head
• the hearts and minds of
• the hearts and minds of someone
• the heat is on
• the heavens opened
• the height of
• the height of something