Somerset town (5)
(Other definitions for chard that I've seen before include "vegetable crop" , "Beet with edible leaves and stalks" , "Leaf stalks from a kind of beet" , "Green vegetable" , "Vegetable with edible leaves and stalks" .)
'somerset town' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for frome that I've seen before include "Somerset town" , "West Country town" .)