One of the joys of my job, which involves reading many, many proofs of National Geographic, is that I’m always learning. Today the new topic is half-high dots, also known as middle dots or raised dots, a mark akin to a period but placed in the vertical midpoint of a line of type. For some reason its name seems happy and makes me want to sing.

Just why am I now consumed with this symbol? In the March issue of National Geographic, we used the abbreviation kWh for kilowatt-hour, and received a challenge from a reader who told us that to be scientifically correct we should have written the term kW·h. (See that half-high dot?) However, that rendition does not agree with Merriam-Webster’s Collegiate Dictionary, our primary guide for spelling, which lists kWh.

The Oxford Concise Dictionary and Chicago Manual of Style also use kWh, as do websites of the U.S. Department of Energy and major electric utilities, though in my search of the Con Edison website I was amused to find kilowatt-hour spelled out multiple times but not abbreviated until I finally stumbled upon a glossary that lists kWh.

Now, before some of you wise guys take me to task for writing “abbreviated,” I will explain that technically, in mathematical jargon, kW·h is a symbol or a mathematical entity, not an abbreviation. The raised dot indicates that the two parts—kW and h—are multiplied. (The International System of Units (SI)—NIST Special Publication 330 explains this, and also that the symbol for watt, W, is capitalized because it derives from a person’s name—even though the perfectly fine everyday term "watt" found in dictionaries is lowercased.)

I appreciate the desire by scientists to be clear and consistent in terminology so that there is no confusion of meaning. Writers and editors feel the same about texts. What we all must do is to determine who our audience is and what makes sense to that segment of the population. For the mathematically literate, using the raised dot in a technical publication is appropriate. For the average reader of National Geographic, eliminating the dot makes sense.

So NG will continue to use kWh, as sanctioned by dictionaries.

By the way, I can’t find the terms half-high dot, middle dot, or raised dot in Webster’s.

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