An American piano company is a business that makes musical instruments called pianos. Imagine a really big and fancy keyboard with lots of keys that can make different sounds when you press them down.
The piano company is like a big factory where people work together to make these instruments. There are workers who build the body of the piano, others who put the strings and hammers in place, and others who decorate the outside of the piano with pretty designs.
Once the piano is finished, it gets put into a box and sent to stores all around the country. People who love music can go to these stores and buy the pianos so they can play music at home or in concerts.
Some famous American piano companies are Steinway & Sons and Baldwin Piano Company. They have been around for a long time and are known for making really high-quality pianos.