Way a relative reaches state of equilibrium (6)
I believe the answer is:
stasis
'state of equilibrium' is the definition.
(I've seen this in another clue)
'way a relative' is the wordplay.
'way' becomes 'st' (abbreviation for street).
'relative' becomes 'sis' (short for sister).
'st'+'a'+'sis'='STASIS'
'reaches' acts as a link.
(Other definitions for stasis that I've seen before include "Condition of arrested progress" , "lack of action" , "Period of equilibrium" , "Secret police force's" , "Stoppage of blood flow in body" .)