The SNIA Dictionary

A glossary of storage networking, data, and information management terminology

Search our online dictionary here.

About the SNIA Dictionary

by the Storage Networking Industry Association

SNIA Dictionary Cover The SNIA Dictionary contains terms and definitions related to storage and other information technologies and is the storage networking industry's most comprehensive effort to arrive at a common body of terminology for the technologies it represents. The terms go through a rigorous technical review and approval process by the SNIA Technical Council to assure their accuracy. The SNIA Technical Council is a group of technical experts elected by the members of the SNIA to guide the SNIA’s technical efforts. Their extensive individual technical backgrounds cover all aspects of storage.

The reader should recognize that in this rapidly evolving field, new terminology is constantly being introduced, and common usage is shifting. The SNIA regards this dictionary as a living document, to be updated as necessary to reflect a consensus on common usage and encourages readers to treat it in that spirit. Suggestions for improvement (e.g., new terms or definitions, or modifications to existing ones) are welcomed at any time and should be submitted on the form located here. The SNIA owns the rights to all submitted comments and suggestions.

Download the Dictionary

PDF Icon Download the current release of the Dictionary 

Submit a Dictionary Term

Before developing any definitions to submit please review the Guidelines for Creating Definitions.  Proposals for new terms or definitions, or modifications to existing ones, should be submitted using our online submission form

Periodically SNIA regional groups translate the SNIA dictionary into local languages. There are versions of the dictionary in Japanese, Portuguese, and Chinese. If you would like to lead a translation project, SNIA would be interested to help support this effort. Please contact

Terms of Use

The SNIA hereby grants permission for individuals to use this dictionary for personal use only, and for corporations and other business entities to use this dictionary for internal use only (including internal copying, distribution, and display), provided that:

  1. any definition reproduced is reproduced in its entirety with no alteration; and
  2. any document, printed or electronic, in which material from this dictionary (or any portion hereof) is reproduced must acknowledge the SNIA copyright on that material, and must credit the SNIA for granting permission for its reuse.

Other than as explicitly provided above, you may not make any commercial use of this dictionary, sell any or all of this dictionary, or distribute this dictionary to third parties. All rights not explicitly granted
above are expressly reserved to the SNIA.

Permission to use this dictionary for purposes other than those enumerated above may be requested by e-mailing; please include the identity of the requesting individual and/or company and a brief description of the purpose, nature, and scope of the requested use.

Copyright © 2004 - 2021 Storage Networking Industry Association, All Rights Reserved.

Definition Format

Terms are defined using the substitution principle, which states that a term's definition should be substitutable for the term itself in a sentence.

In the case that more text is required or deemed helpful, it is contained in one or more separate paragraphs after the definition itself. This text is informative in nature, and while intended to be accurate, is not technically part of the definition itself.

Deprecated Synonyms

In many cases, as technology develops, companies invent new terminology to describe innovations in their products. As the technology matures and vendors attempt to compete and compare
their products with others, some terms become widely used, while other terms may remain in limited use and are synonyms for the widely used terms. This causes confusion in the marketplace. To encourage crispness and uniformity in the industry, this dictionary lists synonyms of this type as "Deprecated synonym for xxxx," where xxxx is the term that has become widely used in the industry. This is to guide the reader toward use of the more widely used term.

In cases where a synonym is not deprecated, the SNIA does not endorse the use of one synonym over another.

Definitions taken from standards documents

The SNIA has a strong interest in keeping definitions harmonized across various industry groups and national and international standards bodies. Towards this end, some definitions have been quoted from standards (e.g., SNIA Standards, INCITS Standards, ISO/IEC Standards, IEEE Standards). In all such cases, the quoted standard is authoritative.

The SNIA wishes to thank ANSI and INCITS for their cooperation in this matter.

Context Hierarchy

Most of the terms in this dictionary have meaning primarily in specific contexts (e.g., SCSI or File Systems). The following categories are used to specify the context for a given definition. These categories are a guide to understanding, not a formal system.

  • General
    • Hardware
      • Network
        • SCSI
        • iSCSI
        • Fibre Channel
        • NVMe
        • Infiniband
      • Data Communication
    • Computer System
      • Storage System
      • Operating System
        • Windows
        • Linux
    • Services
      • Cloud
    • Management
      • Data Management
        • Backup
        • Data Recovery
        • Data Security
        • Database
        • File System
        • Long Term Retention
        • Capacity Optimization
      • Storage Resource Management
    • Energy
    • Standards
    • Legal

In the above hierarchy representation, context labels indented beneath other context labels represent specializations of the higher-order label concept. For additional information on contexts, see the Storage Industry Resource Domain model. Below is an example of how context is indicated:

context example
[Context] The context is called out in square brackets at the beginning of each definition, as in this example.