detailed plans. requirements. and statements of particular procedures and/or standards used to define and guide work.specifications
There are different types of specifications, which generally are mostly types of documents, forms or orders or relates to information in databases. The word specification is defined as "to state explicitly or in detail" or "to be specific". A specification may refer to a type of technical standard (the main topic of this page).
Using a word "specification" without additional information to what kind of specification you refer to is confusing and considered bad practice within systems engineering.
A requirement specification is a set of documented requirements to be satisfied by a material, design, product, or service.
A functional specification is closely related to the requirement specification and may show functional block diagrams.
A design or product specification describes the features of the solutions for the Requirement Specification, referring to the designed solution or final produced solution. Sometimes the term specification is here used in connection with a data sheet (or spec sheet). This may be confusing. A data sheet describes the technical characteristics of an item or product as designed and/or produced. It can be published by a manufacturer to help people choose products or to help use the products. A data sheet is not a technical specification as described in this article.
A "in-service" or "maintained as" specification, specifies the conditions of a system or object after years of operation, including the effects of wear and maintenance (configuration changes).
Specifications may also refer to technical standards, which may be developed by any of various kinds of organizations, both public and private. Example organization types include a corporation, a consortium (a small group of corporations), a trade association (an industry-wide group of corporations), a national government (including its military, regulatory agencies, and national laboratories and institutes), a professional association (society), a purpose-made standards organization such as ISO, or vendor-neutral developed generic requirements. It is common for one organization to refer to (reference, call out, cite) the standards of another. Voluntary standards may become mandatory if adopted by a government or business contract.