The Power Symbol Actually Has A Pretty Cool Meaning

You've seen it pretty much every day now for decades, and you've interacted with it just as many times, but have you ever wondered why the power symbol looks the way that it does? There's a joke that anyone born in the 21st century doesn't know what the save icon is because they've never seen a floppy disk before. The same is somewhat true of the power symbol because, unless you had a hand in designing it or appreciate the history of computing, it's likely you are just as in the dark as most folks.

The power symbol is expressed in several ways, but most people are likely familiar with the circle that has a line extending from its center, breaking its border to the top. If you look at a toggle switch that you might find on a power strip, the symbol is broken up, so that the circle is on one side and the line on another. When the line side is depressed, the power is turned on, while flipping it in the direction of the circle kills the power. There are other variations, including a circle with the line enclosed within.

Both the circle and the line have meaning in binary code, such that the circle represents "zero" while the line stands for "one." In binary, these literally mean "off" and "on." Symbols used to indicate power and others are universally accepted by the Unicode Standard, a character encoding standard used worldwide. The power symbol was first brought into Unicode 9.0 alongside many emojis in 2015, and it remains there alongside familiar icons. These days, the power symbol is a universally recognized means of telling whoever looks upon it precisely what it does.

While the power symbol made it into Unicode in 2015, it's been around for much longer. The goal in moving it to Unicode was to add a crucial symbol used around the world by the masses. Initially, the symbol now used for power was the one used for stand-by, but its use was ambiguous, depending on the system in which it was emplaced. Additionally, it was important to create a proper symbol instead of labeling things in English with "on" and "off." The symbol was redefined to indicate power in December 2004 by the Institute of Electrical and Electronics Engineers (IEEE).

Three symbols were adopted for power, including the familiar one, the aforementioned enclosed circle, and the waning crescent Moon for sleep. The IEEE standardized these in IEEE Standard 1621. Prior to this, you could find the power symbol in all sorts of places, including the old Gateway Computers logo. The symbol appears on Android phones and other devices, but is rather simplistic, consisting of only two elements. That said, they're two of the most important aspects of computing, and without them, modern computer systems wouldn't exist.

The fundamental aspects of computing are perfectly encapsulated in the button we push to turn on a device. That single symbol, combining zero and one, reflects the binary logic that underpins modern electronics.