Colour of a sheet anchor (3)
I believe the answer is:
tan
'colour' is the definition.
(tan is a kind of colour)
'of a sheet anchor?' is the wordplay.
'of' says the answer is hidden in the clue.
'TAN' is hidden within 'a sheet anchor'.
(Other definitions for tan that I've seen before include "Tawny" , "Bronze" , "Yellowish brown" , "Shade of brown" , "Lightish brown colour" .)