Grass seen as river runs around (4)
I believe the answer is:
reed
'grass' is the definition.
(I've seen this before)
'river runs around' is the wordplay.
'river' becomes 'dee' (River Dee**).
'runs' becomes 'r' (cricket abbreviation).
'around' says the letters should be written backwards.
'dee'+'r'='deer'
'deer' back-to-front is 'REED'.
'seen as' is the link.
(Other definitions for reed that I've seen before include "Type of grass" , "Tall grass plant that grows in water" , "Vibrating part of some instruments" , "'It vibrates in a clarinet, say (4)'" , "Instrument; tall grass" .)