MIMEOGRAPH / MIMEO
A mimeograph, abbreviated mimeo, is a paper copy created by a duplicating machine that forces ink through a stencil and onto the sheet. The stencils could be typed on a typewriter or hand cut. Generally used for printing in small quantity, the process is mimeography and the resulting copies do not have archival properties.
The first example image is from a 1941 school handbook mimeographed by students. The second example is from a 1955 "zine," with stencils made by the author.