Q: jQuery ReferenceError for "define" in jquery.js and for $ just started the jQuery tutorial and stuck on the ready event part. Opening the html and file and clicking the "jQuery" link, no alert pop-up comes up like it's supposed to, it goes straight to the jQuery home page instead. 
<!doctype html>
<html>
<head>
    <meta charset="utf-8" />
    <title>Demo</title>
</head>

<body>
    <a href="http://jquery.com/">jQuery</a>
    <script src="jquery.js"></script>
    <script>
    </script>
    <script>
        $( document ).ready(function() {
            $( "a" ).click(function( event ) {
                alert( "Thanks for checking" );
            });
        });


    </script>
</body>
</html>

Update and more details:
after checking with Firebug, the two errors are ReferenceError: define is not definedfor the jquery.js file and the ReferenceError: $ is not defined for the html file. I'm guessing the latter is due to jQuery not working. I installed jQuery with Bower and copied the jquery.js file in the src directory to the same directory as where my html file is. Is this not how it's done? I have tried using the path to this file's original location, but the errors are the same.
Update 2: inserting javascript/jquery instead of jquery.js into the <script src = has helped to get rid of the first ReferenceError, $ is not defined still comes up.
The Solution: using the minimized version of jquery.js (i.e. the jquery.min.js) got rid of the errors for me. Using the google hosted one http://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js or downloading it to your HD both work. 

A: TL;DR; We neeed to reference the correct jQuery file either through relative or absolute (either a URI or directory) path.
Complete Details:
I was working on a simple website having only one web page test.html when I faced the same error in this question:

Uncaught ReferenceError: define is not defined
at jquery.js:1

I use Visual Studio code. I had to reference jQuery. So instead of downloading its JS file (to be referenced in test.html) from jQuery's official website, I went into command shell of Visual Studio Code and installed jQuery module using below node package manager(npm) command:
npm install jquery

After the command finishes executing, you will observe a new directory named node_modules having dist, external, src as sub-directories:

Then, I browsed src directory and found jquery.js file inside it. I thought I can refer jquery in my web page by giving hard-coded path of this file as shown below:
 <script type="text/javascript"  src="C:\Users\rasik\Desktop\learnJs\node_modules\jquery\src\jquery.js" />

Now when I loaded the HTML page, I encountered the error that OP has mentioned.
The issue here is that the jQuery file which needs to be referenced for using jQuery library (when you have installed it through npm) is found under dist (short for distributable) directory. I had referenced it from src directory. So the issue got resolved when I changed the path as shown below:
<script type="text/javascript"  src="C:\Users\rasik\Desktop\learnJs\node_modules\jquery\dist\jquery.js" />

src folder contains the full source code of jQuery where it references many other files also. Since the other dependency JS files meant for jquery.js were not referenced in the test.html page, so it was failing to recognize the code which had a dependency on other JS files.

A: Could it be that your js script is in another hierarchy? i.e /javascript/jquery.js
<script src="javascript/jquery.js"></script>


A: Change your jQuery code to be like this:
$( document ).ready(function() {
  $( "a" ).click(function( event ) {
    event.preventDefault();
    alert( "Thanks for checking" );
  });
});

The event.preventDefault() part will prevent the clicked element from performing its default behavior, which in the case of an a element is to go the the page defined in its href attribute.
