Letter or symbol (9)
I believe the answer is:
character
<span class="explanation-format__ClueExplanation">I believe this clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">letter</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >'<span class="explanation-format__original">symbol</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I know that character is a type of written symbol)</span><br/ ><br/ ></span>
(Other definitions for character that I've seen before include "Letter or number" , "Type - letter" , "Person in a novel or play" , "Distinctive nature" , "crank" .)