Task: Capture a Common Vocabulary
This task describes how to define the common set of terms that need to be used consistently on the project.
Disciplines: Requirements
Purpose

The purpose of this task is to define a common vocabulary that can be used in all textual descriptions of the system, especially the software requirements.

Relationships
Steps
Find Common Terms

In the Requirements discipline, you must define a common vocabulary using the most common terms in the problem domain. You should then consistently use the common vocabulary in all textual descriptions of the system and its requirements. In this way, you keep the textual descriptions consistent and avoid misunderstandings among project members about the use and meaning of terms. You should document the vocabulary in a Glossary.

To find common terms in the problem domain, consider terms used in the requirements and the development team's general knowledge of the system to be built. Focus on terms describing the following concepts:

  • Business objects representing concepts used in the organization's daily work or in the system's expected operating environment. In many cases, a list of concepts of this kind already exists.
  • Real-world objects that the system needs to be aware of. These objects occur naturally, and include such things as: car, dog, bottle, aircraft, passenger, reservation, or invoice.
Example:

In a Depot-Handling System, conversation is about, among other things, the items in the depot and potential storage locations for them.

  • Events that the system needs to be aware of. By "event" is here meant a point in time or a chronological incident that the system must know of, such as a meeting, or an error occurring.
Example:

A natural event in a Depot-Handling System is the delivery of goods to the depot. For each delivery the system should "remember" the date of the delivery, who received the goods, what goods were delivered and how many there are of each kind.

Each term is typically described as a noun, with a definition. Terms should be in the singular, "order" and "task", not "orders" and "tasks." All interested parties should agree on definitions for the terms.

Evaluate Your Results

You should check the glossary at this stage to verify that your work is headed in the right direction. There is no need to review it in detail. Reference: Checklist: Glossary.