Conjunction is a sentence that unites words, phrases and clauses both dependent and independent. The seven coordination conjunctions have abbreviations to make them easy to remember : FANBOYS 
For, And, Not, But, Or, Yet, So
iin FANBOYS, we find "For". what does it mean?
'For' explain the reason, cause or purpose.
'FOR' has a meaning as a conjunction and as a preposition. As a conjunction, 'FOR' means the same as 'BECAUSE'