thread0.html

Arc supports multiple threads of execution.  One useful application of threads is to run a long-running process in the "background", for instance Arc's web server:
<pre class="repl">
arc> (thread (asv 8000))
#<thread>
arc>
ready to serve port 8000
</pre>

See <a
  href='http://download.plt-scheme.org/doc/372/html/mzscheme/mzscheme-Z-H-7.html'>MzScheme's
  Threads</a> for details of the threading model.