Website administrator is perfect or ideal technical term for a person in charge of maintaining a website as he has to make sure site is running smoothly without any issues.
Admin need to keep an eye on the server and also on the website, it is up to date. He has to fix the site if there is a programmatic error. He need to have a knowledge on the server where the site is hosted, database, programming tool the site is built on, command line access, FTP etc.
If you need any help . Please let me know if i can be of any help.