Like instructions, descriptive technical writing uses a combination of visuals and text to both “show” and “tell” the reader about the information being conveyed. Like more creative descriptions, technical descriptions sometimes draw on the “five senses” and metaphorical comparisons (analogies) to allow the reader to fully conceptualize what is being described. More often, however, they rely on concrete, measurable descriptors.

Technical descriptions can take many forms, depending on purpose and audience. Descriptions can range from a brief sentence, to a paragraph, a whole section of a report, or an entire manual.  Poorly written technical descriptions can cause confusion, waste time, and even result in catastrophe!  Technical product descriptions are often legally required to ensure safety and compliance.  Attention to detail is critical.

Some general categories of technical descriptions include the following:

• Mechanism Descriptions:  provide a detailed overview the physical aspects of a tool, machine or other mechanical device that has moving parts and is designed to perform a specific function. These could be product descriptions for sales or manufacturing, documentation of design specifications, info-graphics, etc.  This chapter focuses in detail on this kind of description.

• Process Descriptions:  detail a series of events (natural/biological/ecological, mechanical, social, or psychological phenomenon) that happen in particular sequence in order to achieve a specific outcome. These can be categorized into non-instructional processes (such as a process analyses of how an internal combustion engine works, or natural processes like photosynthesis) and instructional process (such as recommended/required procedures and explicit step-by-step instructions to be followed—see section on writing instructions for more information).

• Definitions:  clarify the specific meaning, often related to a specific context, or express the essential nature of the terms being defined. These can range in length from a simple clarifying phrase to an extended document of several pages. Definitions will often include detailed descriptions and visuals to illustrate ideas. Click on the link below to view a student PowerPoint presentation on how to write effective definitions for technical purposes. This presentation is included with express permission of the student. ^[1]

Writing Technical Descriptions

Before you begin to write a technical description, consider carefully how the audience and the purpose of the document will affect what you write. Your sense of your audience will determine not only how technical your vocabulary should be but also how long your sentences and paragraphs should be.

Another audience-related factor is your use of visuals. Less knowledgeable readers may need simple graphics; they might have trouble understanding complicated schematics or charts. As you consider your audience, think about whether any of your readers are from other cultures and might therefore expect different topics, organization, or writing style in the description.

Consider your purpose: What are you trying to accomplish with this description? If you want your readers to understand how a personal computer works, write a general description that applies to several brands and sizes of computers. If you want your readers to understand how a specific computer works, write a description specific to that computer. Your purpose will determine every aspect of the description, including its length, the amount of detail, and the number and type of graphics.

Drafting Effective Descriptions 

There is no single organization or format used for descriptions. Because descriptions are written for different audiences and different purposes, they can take many shapes and forms. However, the following four suggestions will guide you in most situations:

• • Indicate clearly the nature and scope of the description
  • Introduce the description clearly
  • Provide appropriate detail
  • End the description with a brief conclusion

Indicate Clearly the Nature and Scope of the Description

If the description is to be a separate document, give it a title. If the description is to be part of a longer document, give it a section heading. In either case, clearly state the subject and indicate whether the description is general or particular. For instance, a general description of an object might be titled “Description of a Minivan,” and a particular description, “Description of the 2015 Honda Odyssey.” A general description of a process might be called “Description of the Process of Designing a New Production Car,” and a particular description, “Description of the Process of Designing the Chevrolet Malibu.”

Introduce the Description Clearly

Start with a general overview: you want to give readers a broad understanding of the object, mechanism, or process. Consider adding a graphic that introduces the overall concept. For example, in describing a process, you might include a flowchart summarizing the steps in the body of the description; in describing an object, such as a bicycle, you might include a photograph or a drawing showing the major components you will describe in detail in the body.

Provide Appropriate Detail

In the body of the description, treat each major part or step as a separate item. In describing an object or a mechanism, define each part and then, if applicable, describe its function, operating principle, and appearance. In discussing the appearance, include shape, dimensions, material, and physical details such as texture and color (if essential). In describing a process, treat each major step as if it were a separate process.

A description can have not only parts or steps but also subparts or substeps. For example, a description of a computer system will include the keyboard as one of its main parts. The description of the keyboard will include the numeric keypad as one of its subparts, and a description of the numeric keypad will include the arrow keys as one of its subparts. The same principle applies in describing processes: if a step has substeps, you need to describe who or what performs each substep.

Conclude the Description

A typical description has a brief conclusion that provides an overall summary of the item. One  common technique for concluding descriptions of some mechanisms and objects is to state briefly how the parts function together. A professional description usually has a brief paragraph summarizing the principal steps or discussing the importance or implications of the process.

Structuring an Item Description

Ask yourself the following questions as you compose your description to help give it a structure:

• • • What is the item? You might start with a sentence definition.
      EXAMPLE: “The electron microscope is a type of microscope that uses electrons to create an image of the target. It has much higher magnification power than normal microscopes.”

• • • What is the function of the item? If the function is not implicit in the sentence definition, state it.
      EXAMPLE: “Electron microscopes magnify objects that are smaller than the wavelengths of visible light.”

• • • What does the item look like? Sometimes an object is best pictured with both graphics and words. Include a photograph or drawing if possible. *If you cannot use a graphic, use an analogy or comparison.
      EXAMPLE: “The USB drive is a plastic- or metal-covered device, about the size of a pack of gum, with a removable cap that covers the type-A USB connection.” Mention the material, texture, color, and other physical characteristics, if relevant.

• • • How does the item work? In a few sentences, describe how the item works (sometimes objects do not work; they merely exist).
      EXAMPLE: “The USB drive is simply inserted into any available USB port on the computer to allow for file transfers between devices.”

• • • What are the principal parts of the item? Limit your description to the principal parts. A description of a bicycle, for instance, would not mention the dozens of nuts and bolts that hold the mechanism together; it would focus on the chain, gears, pedals, wheels, and frame.
      EXAMPLE: “The MIG welder has a power switch, a speed selector, a voltage selector, a pressure regulator, a ground clamp, and a standard trigger handle and tip.”

You may find that some of these elements are not necessary; again, consider what your target audience already knows. Strive to strike a balance between unnecessarily stating the obvious and incorrectly assuming your readers have knowledge that they lack.

Once you have your purpose and audience clearly in focus, draft a technical description that includes the following elements:

1. 1. Definition: What is it, and what is its main purpose?
   2. Overview: Describe the mechanism’s overall appearance (“big picture”).
   3. Components: Describe the main component parts in labeled sections; consider the order of information carefully here. Create a logical connection between each component described.
   4. Explanation: how do the parts work together to fulfill its function? What key principles govern its functioning? Consider how much detail is necessary here for your intended audience.
   5. Visuals: include graphics that clearly illustrate the mechanism and/or its parts. Show the device as a whole; consider showing specific details in expanded views, cut-aways, or labeled diagrams. You may even embed or link to videos showing the device in action.
   6. Conclusion: depending on the purpose, you might review product’s history, availability, manufacturing, costs, warnings, etc.)
   7. References: Sources you have used in your description, or additional sources of information available (if relevant).

Revising Technical Descriptions 

In refining the details of your description and its component parts, consider the following:

• • • Organization: Use a logical principle to organize your description
      • Top to bottom (or foundation upward)
      • Left to right (or right to left)
      • Inside to outside (or outside to inside)
      • Most important to least important features
      • Central component to peripherals
      • Material properties, etc.

• • • Language:  Use specific, precise, concrete terms and avoid vague or overly-general terms
      • Use correct terminology – define terms as necessary for your audience
      • Use analogy to describe an unfamiliar thing in terms of a familiar thing
      • Use objective language – no “ad speak” or subjective terms
      • Use present tense, active verbs to describe how the device appears and what it does
      • Use words that create vivid and specific pictures in the reader’s mind.

Here’s an example of a student’s technical description assignment for explaining GPS.

Additional Resources

• “Technical Description” Online Technical Writing

• “Technical Definition and Description” Penn State University, Technical Writing, Fall 2013

"Technical Descriptions." Technical Writing Essentials. [License: CC BY 4.0]