Terms of Explanation do one of the following -​​ 

(a)​​ Gives​​ the reason for something, making it plain or understandable
(b)​​ Gives​​ reasons why it is true or why it occurred​​ 
(c)​​ Used to express cause, to explain (to give the reason for or cause of)
(d)​​ Simply adds additional information.​​  

Examples​​ of words –​​ for;​​ because.

Note​​ - This discussion relates to "for" when it is used as a conjunction, and not when "for" is used as a preposition (placed before another word or phrase to express some relation or quality, action or motion to or from the thing specified - "God made garments of skin for Adam and his wife").​​