【Power】 ,  【force】 ,  【energy】 ,  【strength】 ,  【might】 ,  【puissance】  mean the ability to exert effort for a purpose.

【Power】 is the most general of these terms and denotes an ability to act or be acted upon, to effect something, or to affect or be affected by something.

【Force】  (see also  【FORCE】 2 ) implies the exhibition or the exercise of 【power】 ; the term usually carries with it a suggestion of actually overcoming resistance (as by setting a thing in motion or accelerating its motion or driving a person or thing in the desired direction); thus, one having the  【power】  to do something exerts  【force】 only when he actually does it.

Therefore  【force】 is often applied to a person or thing that exerts its 【power】 with marked efficacy or efficiency.

【Energy】 in general use and especially as applied to persons implies stored-up 【power】 releasing itself in work or craving such release.

【Strength】  applies to the 【power】 that resides in a person or thing as a result of qualities or properties that enable him or it to exert 【force】 or to manifest 【energy】 or to resist pressure, strain, stress, or attack. Physically  【strength】 implies soundness (as of health or of construction or design) while mentally and morally it may imply capacity for endurance or resolution or intrepidity.

When applied to military forces it usually implies 【power】 manifest in such things as numbers, equipment, and resources.

【Might】  and  【puissance】  are rather rhetorical or poetic words meaning operative or effective 【power】 or 【force】 .

【Might】 often suggests great or superhuman 【power】 ; it is therefore appropriate when the reference is to supernatural beings or supranatural forces or to human 【power】 that is so strong that it cannot be gainsaid.

【Puissance】  is often indistinguishable from  【might】 , but it can also connote an impressive display of 【power】 .