In historic time, the wild green outskirts of the city (7)
I believe the answer is:
regency
'in historic time' is the definition.
The answer and definition can be both related to time as well as being singular nouns.
Perhaps there's a link between them I don't understand?
'the wild green outskirts of the city' is the wordplay.
'the wild' indicates an anagram.
'outskirts of' says to hollow out the word (remove centre letters).
'city' with its centre taken out is 'cy'.
'green' with letters rearranged gives 'regen'.
'regen'+'cy'='REGENCY'
Can you help me to learn more?
(Other definitions for regency that I've seen before include "Period of 1811 - 20" , "Old style" , "Years from 1811 to 1820 during George III's periods of insanity" , "British period, Eighteen-Eleven to Eighteen-Twenty" , "Period of king's incapacity" .)