Power, strength (5)
I believe the answer is:
might
I believe this is a double definition.
'power' is the first definition.
(I know that power can be written as might)
'strength' is the second definition.
(I know that might is a type of strength)
(Other definitions for might that I've seen before include "word expressing possibility" , "Great power, strength" , "Force; could" , "Strength - could possibly" , "Doubtful" .)