Relax briefly with daughter's kid (5)
I believe the answer is:
child
'kid' is the definition.
(I know that kid can be written as child)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for child that I've seen before include "Young human" , "Infant" , "Not an adult" , "Juvenile" , "issue" .)