The word archives has been used in various ways and recently (and perhaps most pervasively) is now used on websites to organize and provide access to older content. Traditionally, in the archival field the word archives is thought about in the following three ways.
(n) institution: an institution or agency responsible for the preservation and communication of records selected for permanent preservation
(n) place: where records selected for permanent preservation are kept
(n) records: the whole of the records made or received by a creator in the course of activities and preserved
Archival materials are the records that are acquired, described, arranged, preserved and made available by archives.
A primary source offers first hand evidence or accounts of events, time periods and practices. Examples of primary sources include diaries, audio recordings, meeting minutes, legal documents, contracts, correspondence and manuscripts. Most archival materials are considered primary sources and are usually unpublished.
The video below, created by Dalhousie University provides a simple explanation of primary, secondary and tertiary sources and their uses.
Archives are not typically arranged by subject matter or even alphabetically or chronologically. This can make archival research challenging (and why it can be a good idea to reach out to archivists for assistance when things aren't clear). Understanding how to approach archival research takes practice, and can be different depending on the focus of research. Why is this the case? Traditional archival theory popularized two guiding principles that influence how archival materials are arranged: Provenance and Original Order.
Provenance can be thought of as the origin of the records, or as the person, family, organization, or agency that created, received, or retained a body of records in the course of their activities (work or life). Archival materials are kept together and are not put with records from other creators or origins. Archival materials tend to be arranged by the creating body/bodies. For example, the Roy Kiyooka fonds at the Moris and Helen Belkin Art Gallery Archives consists of material created and accumulated by Roy Kiyooka over his artistic career.
Original order means that the records are maintained in the order which they were created, filed, or used by the creator. Retaining the original order helps preserve the relationships between the records and the sociohistorical context of creation and use. In other words, the ways in which records are kept may tell the researcher something about how the records were made and/or used. It can help researchers understand how the creator worked, this kind of information would not be reflected in the content of the records, but in the arrangement of the records. Sometimes there is no original order, for instance if the materials were sorted or packed by someone else, or have moved between custodians. In these cases the archivist will impose an order on the materials. Sometimes the system of arrangement is indicated in an arrangement note within the description.
Archival records are often arranged and described through the use of archival aggregations (also called levels of arrangement). Depending on the arrangement (order/original order) of records, each group of records (fonds, see below) will look different. The image below is an example showing all of the archival aggregations.
Image attribution: "Levels of arrangement in a fonds" by the Peel Art Gallery Miuseum & Archives is licensed under CC-BY 4.0.
Fonds is the highest level of archival aggregation. It is a word meaning the whole of the records, regardless of form or medium, organically created and/or accumulated and used by a person, family or organization in the course of that creator's activities or functions. The word collection is also used to describe archival groups, this refers to materials that have been deliberately gathered together based on a theme or subject. For example, the Women's Movement Project fonds at SFU Archives is all of the records created between 1990 to 1999 related to the project. You can see in the screen shot below, the levels of arrangement depicted in the tree at the top of the page. This fonds has series and file level descriptions nested within the fonds.
A series level description represents records that were accumulated and used in service of a particular function. As you can see in the example above, some of the series under the Women's Movement Project fonds include "Women's Movement background records", "Committee minutes and reports" and "Correspondence." If a researcher was looking for information on the history of the Women's Movement Project, they might want to look in the series containing background records.
A file level description is the smallest aggregation within a fonds. Files consist of records placed together that reflect particular activities, subjects, etc., and have the same title. Files are an intellectual aggregation or construction, the grouping imposes an intellectual order on the records. A file may span many folders, which are physical aggregations of records. However, often file titles and contents are reflective of physical folders that were labelled and kept by the creator. In the Women's Movement Project fonds, you can see the file titles under the "Correspondence" series.
Items are the lowest level of archival description. Like files, items are an intellectual, construction, an item doesn't always correspond to one physical thing. An item can be a letter that spans multiple pages or an audio recording split over three cassettes. An item can also be a single physical object such as a poster. Typically archives are not described to the item level unless there is a reason to include this level of detail, such as digitization or the item requires a more granular description for access.