Why is it called gradient boosting?

Related questions

1. What is the difference between gradient boosting and Random Forest?
2. What is bagging in decision tree?
3. Does bagging reduce bias?
4. Is XGBoost random forest?
5. Can boosting Overfit?
6. What is shrinkage in gradient boosting?
7. What is cross validation in ML?

Tags

1. #which
2. #gradient
3. #based
4. #residuals
5. #adaboost
6. #weights
7. #changes
8. #already
9. #training
10. #rather
11. #boosting
12. #existed
13. #invented
14. #observations