Rest and relaxation includes stroll for stroller (7)
I believe the answer is:
rambler
'stroller' is the definition.
(thesaurus)
'rest and relaxation includes stroll' is the wordplay.
'rest and relaxation' becomes 'rr' (R and R is short for rest and relaxation).
'includes' means one lot of letters goes inside another.
'stroll' becomes 'amble' (synonyms).
'rr' placed around 'amble' is 'RAMBLER'.
'for' acts as a link.
(Other definitions for rambler that I've seen before include "taker of country walks" , "Rose maybe" , "Kind of climbing rose" , "who's not heading for the point" , "Person who takes long walks in the country" .)