Web Server Hosting

What is the difference between a web host and web server? And a colocation? Details would be appreciated!

I’m going to make a facebook app (wish me luck)
and I noticed they access a server that I would be responsible,
is a server the same as just web hosting?
like can I just upload my app to a web hosting company or is server hosting different?
thanks
(i just don’t want to invest in another computer just to [...]

is thr any issue with a hosting server abroad? indian web hosts charge lot more higher and far less space and features.bt i heard its better to opt for indian server.any1 can explain