What is a server?
A computer whose job is to answer requests.
Every time you open an app or a website, your phone asks some other computer for something. That other computer is a server.
What it is
A server is just a computer whose job is to answer requests. It runs a program that listens on the network, waits for a request, and sends back a response.
How it works
Your device is the client. It sends a request: give me this page, save this photo, log me in. The server does the work, maybe reads a database, and replies. Most servers have no screen at all. They sit in data centers and run all day.
Why it matters
One server can answer thousands of clients at once. And when people say the cloud, they mean someone else's servers, rented by the hour.
