t would
certainly be difficult to define "every" word in the dictionary,
but all that I claimed is that we must be "able to" define
every word.  Potentiality is easier to achieve than actuality.
For reference, following are the three criteria:

&gt; 1. The ability to define any and all terms used in well
&gt;    established laws and theories of the major scientific
&gt;    fields, especially physics, chemistry, and biology.  That
&gt;    may also include defining some terms, such as phlogiston
&gt;    and e