Endoribonuclease-prepared siRNA
esiRNA or Endoribonuclease-prepared siRNAs are a mixture of siRNA oligos resulting from cleavage of long double-stranded RNA (dsRNA) with an endoribonuclease such as Escherichia coli RNase III or Dicer. An alternative concept to the usage of chemically synthesized siRNA for RNA Interference (RNAi) is the enzymatic digestion of long double stranded RNAs in vitro.
Source: Wikipedia — Endoribonuclease-prepared siRNA (CC BY-SA 4.0)