As defined by Merriam Webster Dictionary:

ˈstreŋ(k)th  ˈstren(t)th 


1: the quality or state of being strong : capacity for exertion or endurance


2: power to resist force : SOLIDITY, TOUGHNESS


3: power of resisting attack : IMPREGNABILITY


    4  a : legal, logical, or moral force

   b: a strong attribute or inherent asset

the strengths and the weaknesses of the book are evident