Unit of astronomical distance (6)
I believe the answer is:
parsec
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">unit of astronomical distance</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for parsec that I've seen before include "Astronomical length - scrape (anag)" , "Unit for measurement of distance of stars" , "3.26 light years" , "three and a quarter twenty sevens [LIGHT YEARS]" , "measure of universe" .)