Travelled on horseback, hugging a French lake, making circle (7)
I believe the answer is:
roundel
'circle' is the definition.
(thesaurus)
'travelled on horseback hugging a french lake' is the wordplay.
'travelled on horseback' becomes 'rode'.
'hugging' means one lot of letters goes inside another.
'a french' becomes 'un' ('a' in French).
'lake' becomes 'l'.
'rode' placed around 'un' is 'rounde'.
'rounde'+'l'='ROUNDEL'
'making' is the link.
(Other definitions for roundel that I've seen before include "Small circular window or design" , "circular device" , "Circular emblem (heraldry)" , "Coloured disc" , "Circular insignia (on military aircraft)" .)