Quarter (6)
I believe the answer is:
fourth
'quarter' is the definition.
(a quarter is a fourth of something)
This is the entire clue.
(Other definitions for fourth that I've seen before include "Almost winning medal?" , "C-F musical interval -- Prince Regent George's eventual regnal number" , "The Press is referred to as this estate" , "Ordinal number for the press - the . . . . . . estate" , "(and 4) The press" .)