0 the surface of the earth: --
1 a reason, cause, or argument: --
[ + that ] He refused to answer on the grounds that the question violated his rights to privacy.
[ + to infinitive ] We have grounds to believe that you have been lying to us.
UK Do you have any ground for suspecting them?
2 an area of knowledge or experience: --
I enjoyed her first novel, but I felt in the second she was going over the same ground (= dealing with the same area of experience).
The lectures covered a lot of ground (= included information on many different subjects).
Once we'd found some common ground (= things we both knew about) we got along very well together.
When the conversation turns to politics he's on familiar ground (= he knows a lot about this subject).
3 a wire that makes a connection between a piece of electrical equipment and the ground, so the user is protected from feeling an electric shock if the equipment develops a fault --
4 the small grains of coffee left at the bottom of a cup or other container that has had coffee in it --
5 past simple and past participle of grind --
We covered a lot of ground in the first few weeks of the course.
The party has watered down its socialist ideals in order to appeal to the centre ground.
He's annoying to argue with because he keeps shifting his ground.
The debate is becoming polarized and there seems to be no middle ground.
He refused to say anything on the grounds that he might incriminate himself.
The accused pleaded not guilty on grounds of diminished responsibility.