What is Usage ?
Usage is noun 1. a custom; a way of doing things It still is the usage in France to shake hands when you meet some- one. 2. a way of using a word It is a techni- cal term that is now in common usage. The book clearly explains common legal terms and their usage. 3. the way something is used The shampoo is for normal usage. With constant usage, you can expect the machine to need replacing every two years.
source: Easier English, Student Dictionary Upper Intermediate Level