0 present participle of scratch
1 to cut or damage a surface or your skin slightly with or on something sharp or rough:
We scratched the wall trying to get the bed into Martha's room.
A few chickens were scratching about/around (= searching with their beaks) in the yard for grain.
People have been scratching their names on this rock for years.
I scratched some paint off the door as I was getting out of the car.
Hannah scratched her head thoughtfully.
2 to remove yourself or another person or an animal from a competition before the start:
The car's paintwork has been scratched.
Paintwork on the corner of a stairway tends to get scratched.
I accidentally scratched her with my long nails.
I scraped the car against a post and scratched the paintwork.
Consider that there is no trivial link between the sight of watching someone else scratch their nose, and the experience of scratching your own nose.
A second example is pilocarpine-induced reciprocal hind limb scratching.
Special care was taken not to destroy or cut the vitelline membrane during the scratching procedure.