Python sys.modules contains a module which is not yet imported
<p>I'm trying to understand the difference between a loaded module vs. an imported module, if there is any.</p>

<p>I'm working in Python 2.7.3, and am just running Python from the command line.</p>

<p>If I execute:</p>

<p><code>import sys</code>
<code>sys.modules</code></p>

<p>I get a list which includes <code>os</code>, for example.  The documentation says that sys.modules is a list of "loaded" modules.  However, if I try to run something like <code>os.environ</code>, I get a NameError which tells me that os is not defined.  However, if I then run <code>import os</code>, this resolves the issue.  Can anyone explain why os exists in sys.modules prior to me actually importing the module?</p>
