Screen printing is a printing technique where a mesh is used to transfer ink onto a substrate, except in areas made impermeable to the ink by a blocking stencil. A blade or squeegee is moved across the screen to fill the open mesh apertures with ink, and a reverse stroke then causes the screen to touch the substrate momentarily along a line of contact. This causes the ink to wet the substrate and be pulled out of the mesh apertures as the screen springs back after the blade has passed. One colour is printed at a time, so several screens can be used to produce a multi-coloured image or design.
There are various terms used for what is essentially the same technique. Traditionally, the process was called screen printing or silkscreen printing because silk was used in the process. It is also known as serigraphy and serigraph printing.
source: Wikipedia, the free encyclopedia