I&#x27;ve actually known some stereotypical sorority-ish girls who use &quot;sis&quot; &#x2F; &quot;sister&quot; in a very parallel way (shallow, narcissistic, petty, immoral). Doesn&#x27;t somehow invalidate all use of the word. (And obviously not all sororities are like that, hence &quot;stereotypical&quot;. Nor are all fraternities.)