A website is basically you being all bored on your computer and wanting to get stuff that's on another computer. So you go to a website and it fetches stuff that's on some other computer and you can watch it, hear it, read it, play it, whatever. Sometimes you can even send stuff back to the other computer. Like a tweet. When you tweet, you're sending a piece of text to the other computer and it stores it away. And then weirdly enough other people around the word are like "wait I want to hear what Lucy (I'm assuming that's your name) tweeted!" And the other computer is like... "ok! here you go".
So that's what a website is.
The other computer
As a programmer, you're the person who writes code that runs on the other computer. Let's call this other computer a "server". Totally random, I know. But not really because it "serves" Lucy's tweets to all the crazy people who want to read them.
Can I Haz Website (Requests)
Ok, so there's this thing called a "Request-response cycle". It's what it sounds like. Lucy makes a request. The server responds with some information. That's like 1 year of a CS degree right there. Maybe. I don't have one so I could be totally wrong.
Think of it like going to the drug store and going up to the counter and asking the guy in the white lab coat (who is totally a real doctor) for something. You're making a request for a resource. And the lab-coat-person has to listen to you and understand what you want and then respond with medication.
If the lab-coat is any good at their job, they will give you the medication you really need. But they could also be bad at their job and give you the wrong thing. Or they could be REALLY bad at their job and give everyone the same medication no matter what they're asking for. There's nothing really you can do about it. The doctor is the middleman between you and the resource you're after.
So that's what an application is. It receives requests, interprets them, and then responds with whatever. Usually the response has something to do with the request. But it could also be a random response. Or it could always be the same response. It's really up to the programmer (i.e. YOU) who trains the lab-coat. I mean server. Wait, what?
Databases. What a buzz word right? You've probably heard of a database. It's not really that big of a deal. In fact, forget about database altogether. Think of it as storage space. So remember when Lucy tweeted that thing about monkeys? Well, in order for me to go see it later, the server has to store it somewhere. The easiest thing for the server would be to write her text to a file, and then read the file when I request it. Turns out reading and writing files is slow. So that's why we have database. Also because they have some advantages in terms of organization. It doesn't really matter. It's all the same in the end.
So I'm sitting at home bored and I open up my browser and type in
twitter.com/codenewbies. My computer figures out what server
twitter.com is sitting on
(how it figures that out is a different topic) and sends it a request that contains some information
about me, and what I'm asking for @codenewbies page. The
twitter.com server looks up
@codenewbies in their database. Fetches all the tweets out of some
database, and replies with a bunch of text and images and styles. My browser takes all this
stuff and renders it on the screen for me.