Maybe &quot;planetary system&quot; is a system of planets, but a &quot;planet system&quot;, like the &quot;Jupiter system&quot;, would be the system for a <i>single</i> planet.  That would make &quot;stellar system&quot; sensible too.  Furthermore, a planetary system associated with a single star is a &quot;star system&quot;.<p>One more option: &quot;exosolar system&quot;.