There are two ways to use the word "grit." In this first set of examples, grit means determination. A person who has grit works very hard, even when a situation is difficult.
With support from her family and a lot grit, Denise was able to get through medical school and become a doctor.
Dan’s ability to win the tennis match showed real grit.
Immigrants to the United States become successful through faith in American ideals and pure grit.
It takes grit for a person to become successful.
You can achieve your goals through a combination of grit and a little luck.
Another way to use the word "grit" is for small particles of sand found in the environment and on sandpaper:
sandpaper
I used 200-grit sandpaper to sand down a table that I painted.
Sandpaper for a rough surface should be between 40 and 80 grit.
You will need to use a very fine grit of sandpaper when sanding down something before you paint it.
A fine grit of dirt and sand blows around during a dust storm.
A storm blew all kinds of grit into the air and into everyone’s face.
You could feel the grit in your teeth.
The fish we ate last night tasted a little gritty. (The word "gritty" is an adjective.)
sandpaper