Cord; series (6)
I believe the answer is:
string
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">cord</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I know that string is a type of cord)</span><br/ ><br/ >'<span class="explanation-format__original">series</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(sequence of similar items or events)</span><br/ ><br/ ></span>
(Other definitions for string that I've seen before include "Cord, twine" , "train" , "Thin length of cord etc" , "It's difficult to say how long a piece of it is" , "light cord" .)