Eg, liver or heart (5)
I believe the answer is:
organ
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">eg liver</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I know that liver is a type of internal organ)</span><br/ ><br/ >'<span class="explanation-format__original">heart</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(the heart is an example)</span><br/ ><br/ ></span>
(Other definitions for organ that I've seen before include "Soft part of the body which has a specific function" , "Instrument - heart, for example" , "Musical instrument - pancreas, perhaps" , "Eg, heart, liver" , "Part with special function" .)