German: ‘slipbox’. Consists of small items of information stored on Zettels (German: ‘slips’), paper slips or cards, that may be linked to each other through subject headings or other metadata such as numbers and tags. Used for research, writing, and general organization and synthesis of thought.

Believed to be a precursor to the wiki.

Reminds me of a Memex in some ways, particularly the saving and future rapid retrieval of information, specifically for research and idea synthesis purposes.