Difference between callback functions and event handlers

I started web development recently, and i can’t seem to wrap my head around event handlers and callback functions. I understand that events handlers are a type of callback, and they respond to events unlike the more general definition of callbacks that get called by some other code when it finishes running. But, I’m looking for an explanation that ‘sticks’ with me.

Here’s an example

<script>
$(document).ready(function(){
 $("button").click(function(){
  $("p").hide("slow", function(){
    alert("The paragraph is now hidden");
   });
  });
 });
</script>

In this code example, i know that ready and click are both events so $("button").click(function(){ is an event handler for the ready event? and $("p").hide("slow", function(){ is an event handler for the click event? How about hide? is it also an event?