A web host remain connected to the Internet 24 hours a day, year round and is the server where a site is located.
A serious web hosting server must be able to handle tons of tasks blazing fast, simultaneously and flawlessly. Needless to say: without any down-time.
You, as client should be able to manage your account, creating e-mail accounts, checking visitors statistics and much more.
My web host is located in U.K. at one of the world's premier data centers.That means that reliability and service are the best and virtually all clients for which I have built websites have also chosen to allow me to host their sites.