Subatomic particles (9)
(Another definition for neutrinos that I've seen is " Particles".)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">subatomic particles</span>' is the definition.<br/ ><span class="explanation-format__explanation">(electron is a kind of subatomic particle)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for electrons that I've seen before include "Elementary particles, negatively charged" , "Elementary particles with negative charge" , "Negatively-charged particles" , "transported by conductor" .)