Some of the key terms and phrases you may come across while doing your research.

Access points: "keywords" for names and subjects, acting as index terms.

Administrative History / Biographical History: biographical or historical note providing information about the creator or creators of the material, describing the life of an individual or family or describing the administrative history of an organisation.

Archival description: a document which describes and explains the content and context of a collection of records, in order to make this material more accessible.

Archive:

a collection of materials created or received by a person, family, or organisation in the conduct of their affairs and preserved because of the enduring value of the information they contain or as evidence of the functions and responsibilities of their creator.
a building that holds archive materials.
an organisation that collects and stores such materials.

Collection:

materials assembled by a person, family or organisation (i.e. an originator) in the course of their life or work.
an artificial collection of materials from various sources (i.e. from more than one originator), often with some unifying characteristics.

Finding aid: a document such as a guide, inventory or catalogue, describing a set of archival records.

Fonds: a term used by archivists to mean a collection of materials created by one person, family or organisation (as opposed to an artificial collection).

Item-level: Archive collections are catalogued hierarchically, from the general to the specific (i.e. the whole collection will be described, then each series, then each sub-series, then individual items). It should be clear that an individual item (e.g. one letter) belongs to a series (e.g. a series of correspondence) and that the series belongs to a collection (e.g. the archive of one particular person). Therefore an item-level description could be describing a single letter.

Originator: the individual, group, or organisation that is responsible for creating a collection; may not be the author of all documents, e.g. letters written to the originator, an album of press cuttings compiled but not written by the originator.

Provenance: the origin or source from which the material comes, and the history of subsequent owners. Knowledge of provenance is considered to be very important for the integrity of the archives.

Repository: library, archive or special collections department, which holds archival material.

Scope and Content: abstract or summary of the range and topical coverage of the material described in the finding aid.

Special collections: rare and unique materials. Often used to refer to holdings of written archives, drawings, photographs and rare books.