H (8)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">h</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for hydrogen that I've seen before include "Lightest and most abundant of all substances" , "Light gas" , "Chemical element with atomic no. 1 in the periodic table" , "... ditto: symbol H" , "Element with atomic number 1" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">h</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for eta that I've seen before include "Letter of Greek alphabet" , "When one is due" , "When's end of journey predicted" , "Basque separatist movement" , "Greek character?" .)