To accession an item means that the materials are physically and officially transferred into the archival repository, wherein the intellectual and physical custody of materials is transferred under legal or policy authority. The term accession is interchangeable with acquisition, and acquisition is more often used.
There are a number of definitions for the term 'appraisal':
Most often the term 'appraisal' is used to describe the process of determining whether records and other materials have permanent archival value to the existing collection.
Appraisal most often takes place prior to donation or physical transfer. This process is different from a monetary appraisal, which estimates market value.
The archivist will need to consider a number of factors before accepting a new item/collection/ into the repository.
Description is the process of creating a set of data representing an archival resource or component thereof. Description styles vary from institution to institution
Preservation the process of protecting materials by minimizing chemical and physical deterioration and damage to minimize the loss of information and to extend the life of the material.