Direction taken in a Chelsea street (4)
I believe the answer is:
east
'direction' is the definition.
(compass direction)
'in a chelsea street' is the wordplay.
'in' says the answer is hidden in the clue.
'EAST' is hidden within 'chelsea street'.
'taken' is the link.
(Other definitions for east that I've seen before include "On most maps it's right!" , "E" , "Tom's schoolfellow" , "Sunrise direction" , "An opponent of North" .)