In archival science, a fonds is the aggregation of documents that originate from the same source. More specifically, a fonds distinguishes itself from a collection through its organic nature, as archival documents that have been naturally accumulated by an individual, company, institution, etc. as a byproduct of business or day-to-day activities.
In modern archival practice, the fonds is generally the highest level of arrangement, and is usually used to describe the whole of the archives of an organisation or the papers of an individual. It may be divided into sub-fonds, generally the records of different branches of an organisation or major themes within the papers of an individual. These are in turn further subdivided into series, usually used for groupings of individual types of documents, sub-series, files, and items. An item is the smallest archival unit, and is usually physically indivisible. It is technically possible to add an infinite number of subs to the fonds, series or file, but in practice it is actually rare for more than one to be used.