right hand thread=turns in clockwise(most bolts/nuts screw in this way)

left hand thread=turns in counter clockwise

 

The reason for rights and lefts is so that you can use one of each on different ends of a rod/linkage/etc, allowing the rod/linkage to be lengthened or shortened by turning the rod. If you had 2 rts, turning the rod would not lengthen or shorten it.

 

thank you cummins that is exactly the answer i was looking for.