Understanding different types of domain

In business, technology and general, the word “domain” appears frequently and with many different meanings in various contexts. This gets tricky at times when collaborating with different companies or communities that use different definitions.

The problem in general is that when we use generic and fuzzy words like domain we make assumptions that put the emphasis on the listener to correctly determine the context and choose the right meaning.

Because domain is such a common word in our world, I think there are a couple of reasons why it’s highly beneficial to have a deeper understanding of the word and its usages:

  1. More chance you will understand other people when they use the word
  2. Knowing when to use other words that better convey your intentions

Types of Domain

The Oxford dictionary definition of domain implies that domain is an area of knowledge or activity like physics or the responsibilities of a person. There are no constraints on what can or can’t be considered together a domain — it’s effectively almost just a group of things or concepts perceived to be related in some way.

“an area of knowledge or activity; especially one that somebody is responsible for”

– Financial matters are her domain.

– Physics used to be very much a male domain.

– things that happen outside the domain of the home

Sector, Industry, Field

I like StoneyB’s description on Stack Exchange of sector, industry, and field as being different types of domain. We can learn a few things from these examples.

Field is most often used to designate a domain of professional specialisation.

Sector is similar to industry but is usually employed to distinguish domains on a structural rather than input/output basis.

Industry, which designates a domain of commercial endeavour

Firstly, there are types of domain which add constraints on how items are grouped. For example, an industry is a domain where domain concepts are grouped based on commercial endeavour like the ride sharing industry.

Secondly, there are more specific words for describing different types of domains. To reduce undesired ambiguity in communication consider using the specific definitions.

Thirdly, domains are not inherently mutually exclusive. The same concept could appear in multiple domains like a sector, an industry, and a field.

Other Types of Domains

Here are some examples of other types of domain:

  • Domain (Ontology): “A domain ontology (or domain-specific ontology) represents concepts which belong to a realm of the world, such as biology or politics. Each domain ontology typically models domain-specific definitions of terms”
  • Enterprise Architecture Domains: Business, Data, Architecture, and Technology
  • Cynefin Domains: Obvious, Complicated, Complex, Chaotic, Disorder
  • Social Domain: “Some examples of social domains include the domains of schoolfamilyreligionworkplace, and government
  • Semantic Domain: “a specific place that shares a set of meanings, or a language that holds its meaning, within the given context of the place.”
  • Logical vs Physical Domains: “A physical domain is a set of computing and storage resources which share coherent memory…A logical domain is an abstraction of a physical domain”
  • Product Domain: “A product domain is a domain group of relating products or services. Within an organization, there are normally several identifiable product domains,…
  • Biological Domain: “The three-domain system is a biological classification introduced by Carl Woese et al. in 1990 that divides cellular life forms into archaea, bacteria, and eukaryote domains”
  • Psychology Domains (aka pillars): Biological, Cognitive, Developmental, Social & Personality, Mental & Physical Health
  • Public Domain: “of all the creative work to which no exclusive intellectual property rights apply”
  • Failure Domain: “encompasses a physical or logical section of the computing environment that is negatively affected when a critical device or service experiences problems”
  • Domain (data mesh): “domains need to host and serve their domain datasets in an easily consumable way…Domains that provide data as products; need to be augmented with new skill sets: (a) the data product owner and (b) data engineers

Levels of Scale

The word domain can also be problematic when the level of scale is not easy to implicitly determine from the context. I encounter this problem quite frequently when the word domain is used in the context of business and software architecture.

A system is composed of parts which can be grouped into areas, and those areas can be grouped into bigger areas, and those bigger areas can be grouped into even bigger areas. Domain can apply to any of those levels.

I recommend using terminology to make levels of scale explicitly, like the levels of scale terminology from sociology, when discussing architecture: micro, meso, and macro levels of scale.

Micro, Macro, Meso Domains

Applying micro, meso, macro to business and software architecture, I define them as:

  • Micro Domain — an area of expertise or knowledge which can be owned by a single team.
  • Meso Domain — an area encompassing multiple micro domains owned by a small community of teams working towards similar goals, probably with an overlap in domain concepts.
  • Macro Domain — an area encompassing multiple meso domains, a very high-level view of the system.

Business Domains in the World of Software/Product Development

In software development, we typically deal with business domains. Areas of expertise in which the business develops tools (aka products) to support people who have a purpose (e.g. users and customers).

A business domain and the concepts it contains from the perspective of teams building business software

Have Fun with the Word Domain

Sometimes we want to be lazy when using the word domain because its meaning can easily be determined from the context. In those cases, there is no need to add a hundred qualifiers to the word.

On other occasions the word domain may lead to confusion and arguments about semantics. In those cases, there are two little tricks to keep in mind: can you be more specific about the type of domain, and would it help to clarify the level of scale?

If you’ve enjoyed this read, you can find more of our articles on software engineering here, and to read more from our contributing author Nick Tune click here.

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