<i>&#x27;OK, but at that point it&#x27;s equally possible that it stands for &quot;catharsis&quot; and represents a file, previously being kept inwardly on disk, being released to standard output.&#x27;</i><p>Catenate and concatenate mean basically the same thing, it&#x27;s trivially easy to see people confusing the two - they might even <i>hear</i> one for the other if they&#x27;re only familiar with one.  That&#x27;s not going to happen with catharsis.