I'm not sure is this is the right SE to ask but I'll ask non the less.
I'm trying to define a family relationship. I think the person is my
step step first cousin once removed.
My my Grand-Father is his Step-Great-Grand-Father. My Mother and his Step-Grand-Father are Step-Brother/Sister.
This is also by marriage, not by blood line so is there another term for that?
 = Male
() = Female
[F] = My Step-Uncle
[H] = His Step-Father
[H] + (I) = Currently married
[J] + (I) = J, divorced or passed away
(A)-+-[B]-----+-(C) | | [D]-+-(E) [F]-+-(G) | | [ME] [H]-+-(I)-+-[J] | [Him]