In fact it seems to be related to the &quot;among&quot; meaning of &quot;unter&quot;. The etymology is similar for other languages:<p><a href="http:&#x2F;&#x2F;www.etymonline.com&#x2F;index.php?term=entertain" rel="nofollow">http:&#x2F;&#x2F;www.etymonline.com&#x2F;index.php?term=entertain</a>