Unterlage

noun
  1. A document or piece of material that serves as a basis or support for something else. noun
    The contract served as an Unterlage for the business agreement.
    She used a thick Unterlage to protect the table from scratches.
  2. A foundation or underlying layer, often used in contexts such as construction or geology. noun
    The builders laid a concrete Unterlage before constructing the walls.
    Geologists studied the Unterlage to understand the area's seismic activity.