Sign of ground spices (6)
I believe the answer is:
pisces
'sign' is the definition.
(I know that Pisces is a sign)
'ground spices' is the wordplay.
'ground' is an anagram indicator ('grind' the letters into a new form).
'spices' is an anagram of 'PISCES'.
'of' is the link.
(Other definitions for pisces that I've seen before include "stars" , "The twelfth sign of the zodiac, the fishes" , "Twelfth zodiacal sign" , "Fish star sign" , "Twelfth sign of the zodiac, the Fish" .)