All silk screen prints are serigraphs.
However, by cutting out a hard stencil and printed as the same way as silk screen by pushing the inks through with squeegee, can also consider to be serigraph.
Silk screening is a process in which you use cloth/clothing to support an ink stencil. A squeegee is moved over the stencil that is on whatever you are screen printing and it has ink on it. I can do you one better, here's a video! :)