To Gauls at first a Roman habit (4)
I believe the answer is:
toga
'a roman habit' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Maybe there's a link between them I don't understand?
'to gauls at first' is the wordplay.
'first' indicates taking the first letters.
The initial letters of 'gauls at' is 'ga'.
'to'+'ga'='TOGA'
Can you help me to learn more?
(Other definitions for toga that I've seen before include "draped cloth" , "Garment worn by men in ancient Rome" , "piece of old clothing" , "garment of old" , "Roman dress" .)