Do the name of component in Reactjs have to be the same with file containing definition of the component?

I’m starting learning about reactjs. But when i watch tutorial on youtube i often see that when definite component in sperate file and export, people always name the file name with component name defining in the file is similar.
For example:I see that to define a component name Book the video always names the file of Book component is** Book.js**
And i wonder that this is official rule of reactjs or may be convention of Reactjs community.

Can i name the file name and component in the file is difference?