quadruplication (n.)

"to make fourfold, double twice," 1660s, from Latin quadruplicatus, past participle of quadruplicare "make fourfold," from quadri- "four" (from PIE root *kwetwer- "four") + plicare "to fold" (see ply (v.1)).  The sense of "make or provide in four identical versions" is by 1879. Related: Quadruplicated; quadruplicating.