Zettel

Zettel is a German noun meaning a note, card, or slip of paper. It denotes a short, informal written item used for recording information, reminders, or references. In everyday use, Zettel appear as small pieces of paper kept in pockets, wallets, or on desks. The word is often found in compound terms such as Lehrzettel (study notes handed out to students) and Lernzettel (notes used for learning).

Historically, Zettel were used in offices, libraries, and research settings to capture fragments of information quickly. They are typically concise, factual, and intended for later retrieval rather than extended writing. Physical Zettel may include a brief citation, a task, or a key idea, sometimes with a date or source.

Zettelkasten and note-taking: A notable application is the Zettelkasten or "slip box," a personal knowledge-management system developed by sociologist Niklas Luhmann. In this method each note (Zettel) contains a single idea and is assigned a unique identifier; notes are cross-referenced and linked to others, enabling emergent connections and a non-linear writing process. The method has influenced academic research workflows and later digital note-taking practices.

Digital-era adaptations: Modern software often emulates the Zettelkasten approach, using notes stored in a database with backlinks, tags, and search capabilities to support rapid idea retrieval and structured writing. The term Zettel is used broadly to describe short, portable notes in both physical and digital forms.