Where does “сплайсинг” come from?

сплайсинг (Russian) comes from English splicing, from English splice, from Middle Dutch splissen.

Ancestry of “сплайсинг”, step by step

Step	Language	Word	Meaning
1	English	splicing	The act by which things are spliced; The point at...
2	English	splice	A junction or joining of ropes made by splicing...
3	Middle Dutch	splissen	—