Analyse light speed from a very long distance (6)
I believe the answer is:
parsec
'a very long distance' is the definition.
'parsec' can be an answer for 'distance' (I've seen this before). I am not certain of the 'a very long' bit.
'analyse light speed' is the wordplay.
'analyse' becomes 'parse' (to parse is to analyse grammatically).
'light speed' becomes 'c' (I can't justify this - if you can you should believe this answer much more).
'parse'+'c'='PARSEC'
'from' acts as a link.
Can you help me to learn more?
(Other definitions for parsec that I've seen before include "Unit of distance in space" , "Measure of distance in space; spacer (anag.)" , "Enormous distance" , "Astronomical length - scrape (anag)" , "Large unit of distance" .)