title: What does the term "genType" mean in OpenGL/GLSL?
body: <p>In GLSL documentation, the term <code>genType</code> is used often as the type of parameters. For example, the function <code>dot</code> is documented as follows:</p>
  
  <pre><code>float dot(genType x,
            genType y);
  
  double dot(genDType x,
             genDType y);
  </code></pre>
  
  <p>What does the term <code>genType</code> mean? What does it abbreviate? Is it used elsewhere than OpenGL?</p>