Power in second eleven, perhaps (5)
I believe the answer is:
steam
'power' is the definition.
(thesaurus)
'second eleven perhaps' is the wordplay.
'second' becomes 's' (common abbreviation).
'eleven perhaps' becomes 'team' (eleven is a kind of team).
's'+'team'='STEAM'
'in' is the link.
(Other definitions for steam that I've seen before include "Speed" , "Watery vapour" , "Hot water suspended in air" , "Source of power" , "Vaporous exhalation" .)