Descriptions explain objects, mechanisms, or processes in a way that whatever is being described can be easily understood. Descriptions are common elements in technical writing.

Descriptions fall into two general categories: product descriptions and process descriptions. Product descriptions explain the features of an item or location. Process descriptions explain how something works. Note that process descriptions are not the same as instructions. Process descriptions are intended to inform your reader, while instructions are intended to actually help your reader do something to create a concrete result.

Product and process descriptions use a combination of visuals and text to both “show” and “tell” the reader about the information being conveyed. 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, though, 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, to a whole section of a report written for another purpose (e.g., accident report, product specifications, instructions), or even to 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.

The biggest hurdle you may face in writing a description is remembering what the term means as it is used in a technical writing context. We all use the word “description” loosely to refer to practically any discussion or explanation. But in technical writing, product description means that you’re doing a detailed discussion of the physical aspects of a thing, such as color, shape, size, weight, height, width, thickness, texture, density, contents, materials of construction, and so on. Process description means that you’re doing a detailed discussion of how something works, including how parts interact, or how one action leads into the next.

For example, this sentence is not really description in the technical writing sense of the word: “Certain iPhones have a camera lens called a fisheye.” The sentence explains the type of lens, but provides little or no physical detail. However, these sentences offer technical description: “This version of the iPhone has a screen size of 6.5 inches measured diagonally. The phone itself measures 6.22 inches long, 3.06 wide, and 0.32 inches thick and weighs 7.97 ounces.”

Describing through Language

When you write a description, you need to think about the kinds of descriptive detail you can provide. Through your language choice, descriptions should provide a clear understanding of the object being described, including:

• General appearance and physical properties
• Overall function/purpose
• Component parts
• How the parts interact to create a functioning whole.

A reader should be able to clearly picture, and therefore understand, the nature of the object being described, what it does, and how it works. In order to achieve this clarity for the reader, the writer must choose significant details and organize information logically. Select details that can be described precisely and measurably, such as:

The type and amount of detail you provide depends on your purpose and audience.

Describing through Visuals

The easiest way for an reader to understand something is to see it. Through a diagram, for example, you can label parts of the object or process so that a reader can understand their relationship to the whole and how they work together. Descriptions also use pictures, tables, charts, graphs, and any appropriate visual. They can also use audio materials if the description is multimedia.

Make sure that text and visuals match. For example, if you’re describing the parts of something in clockwise order, or from top to bottom, make sure the visual functions in the same way, taking your reader’s eye in the same direction. Additionally, the descriptors labeled on the visual need to match what’s in the text. Consistency is key.

Some visuals often included in descriptions are called “specifications,” as they specify the details of the thing being described. You may need to include a list or table of technical details about the object or process you’re documenting. For example, here’s a table that specifies different grades of austenitic steel.^[2]

Or you may use an image with callouts (lines or arrows with text attached) to highlight parts or characteristics of the thing you’re describing. The example below is an extract from specifications of the blueprints for NASA’s Saturn Five rocket using only the 1000 most commonly-used English words, for a non-technical audience.

Developing and Organizing a Description

A technical document intended to describe has many parts.

Introduction

Plan the introduction to your description carefully. An introduction may cover the following things as appropriate, in whatever order is appropriate for your purpose and audience:

• a definition of the specific object about to be described
• what the audience needs in terms of knowledge and background to understand the description
• a general description of the object (e.g., a broad mention of its function, appearance, and overall operating principle; this is what you’ll explain in depth in the body of the description)
  
• an explanation of the object in context to capture your audience’s interest, so your audience understands the importance of reading the description
• an overview of the contents of the description

Background

If the thing you are describing is not likely to be familiar to most of your readers, consider adding some background before you plunge into the actual description. If you are about to describe a PQI/380 density gauge to non-specialists, you should first discuss what it is, what it does, and how and where it is used.

Description of Parts or Characteristics

The main part of your description is the discussion of each part or characteristic of the thing you’re describing. Divide the thing you are describing into parts, or characteristics, or both.

Parts are the pieces of the item, for example, a wooden pencil has lead, a wooden barrel, an eraser, and a metal clip.

Characteristics are describable aspects of a thing which are not discrete parts, for example, the pencil has a certain weight, length, width, and so on.

Some descriptions include just parts or just characteristics, and some include both. For example, if you had to describe a vacant lot that your company was considering for purchase, you’d probably describe it by its characteristics: its location, square footage, terrain, vegetation, access to utilities, and so on. Determine what you need to describe – parts, characteristics, both—based on your purpose and audience.

Once you’ve divided the thing you are describing into parts, characteristics, or both, your next job is to describe each one. For mechanical things, it works well to start by defining the part and explaining its function. After that, you describe the part from general to specific, using any type of description that’s appropriate. Notice that you can mix other kinds of writing into description. You can explain functions, define terms, or discuss a portion of a process as you describe. That’s fine as long as the primary focus and the majority of the content is truly description.

Organization of Parts and Characteristics

Long technical definitions need their own organization strategies, just as any piece of writing does, but technical descriptions usually rely on a basic organizational scheme, which may be one of the following (or any organizational scheme logical to the thing being described):

1. general to specific
2. spatial
3. chronological
4. most important to least important

Your choice of an organization strategy will depend on what you’re describing. In most description documents, you’ll usually move from general to specific, since you need to begin by defining the thing and then proceed by breaking it down thematically. What that theme is, though, depends on the nature of the thing being described.

1. General to Specific

For example, you may have to describe a bicycle. It would not be useful to a reader to randomly talk about its parts; you’d need some internal logic as a way of ordering your description of those parts. One logical scheme might be to begin with major systems—the frame, wheels, gears, brakes—and then go into more detailed description about the parts that compose each of these systems, and how the systems work together. A general to specific order such as this makes sense in many technical descriptions.

2. Spatial

If you needed to describe a four-barrel carburetor, you’d probably want to describe how the parts fit together, so a spatial organization scheme would make sense, complete with a specification diagram of the parts. Spatial organization is useful when you’re describing how parts or characteristics physically relate to one another.

3. Chronological

Chronological organization makes sense if you’re describing a process. For example, if you were to describe the process of smelting iron, you’d describe each step in the process, e.g., “First, dump trucks haul in raw ore and pour it into this bin. Then we use a bucket loader to transfer the ore into this machine, where we pulverize it. Then we load the crushed ore into these crucibles and roast the ore until the iron melts out.”

4. Most Important to Least Important

You may have an instance in which it’s logical to order your description of parts or characteristics from most important to least important. For example, in a description of a chainsaw, you might want to start by describing the chain brake (the characteristic that stops the chain in case of kickback), since kickback is the cause of most chainsaw accidents.

Discussion of any Related Operation or Process

At some point in a description, often at the end, it is useful to summarize the operation or process associated with the object you’re describing. For example, if you’ve just described a mechanical pencil, you could briefly explain how it is used. If you’ve just described a snowflake, you could discuss the process by which it formed.

Sample Descriptions

• Technical Description: Rayovac Workhorse Flashlight
• How Does a Slow Sand Filter Clean Water? (student sample)

^[1] Austenitic Stainless Steel Grades. Austenitic Stainless Steeles, https://www.aksteel.com/our-products/stainless/austenitic-stainless-steels.

^[2] Sample Specifications Table from page on Austenitic Stainless Steel, Wikipedia, https://en.wikipedia.org/wiki/Austenitic_stainless_steel.