Onionskin is a type of paper that is thin and lightweight, resembling the skin of onions. However, there are several other terms to describe this type of paper. An alternative synonym for onionskin is tracing paper, which can be used for tracing designs, sketches, and patterns. Another synonym is vellum, which is a type of parchment that is translucent and also used for printing or drawing. Parchment paper is also similar to onionskin, but it is usually thicker and more opaque. Finally, tissue paper, while typically used for gift wrapping, can also be used as a thin, delicate alternative to onionskin paper.