As per the Oxford dictionary, a sheet is a large rectangular piece of cotton, fabric, or paper. In AM, the word sheet is used for a rectangular piece of any material, such as metal, polymer, ceramic, paper, glass, etc. Sheet-upon-sheet fabrication gives the concept of layer-upon-layer fabrication an opportunity to showcase a material that resembles a layer. This opportunity is not available for other feedstocks, such as powder, wire, or hydrogel, as they have to go through processing before they reach the status of a layer that the sheet has already achieved. This exactness in resemblance gives some advantages—if a big product needs to be fabricated, it could be better to start from the biggest available feedstock (sheet) rather than from a small feedstock such as powder. The sheet-upon-sheet phenomenon conveys a message that before another sheet is placed and joined, there is an opportunity to place electronics, sensors, or fiber between two sheets if joining does not damage them and make smart products.