Common definitions of Augmented Reality (AR) are unnecessarily myopic and restrictive. One professionally competent definition goes like this: “The ability to seamlessly and dynamically integrate graphic and other multimedia content with live camera views on PCs and mobile computing devices such as your smartphone.” (Mimi Sheller, Professor of Sociology, Drexel University and Director, Center for Mobility Research and Policy. Professor Sheller has done a reasonably good job of describing the state of AR as popularly perceived today, but as is often the case, her definition is limited to her area of specialization and looks only at the near term timeline. For this fast changing field, what about tomorrow and what about the broad range of fields that are looking at AR applications?
A better definition of AR would be: Augmented Reality (AR) is the artificial, seamless, and dynamic integration of new content into, or removal of existing content from, perceptions of reality.
The best example of practical augmented reality today is still the yellow first down line used in TV broadcasts 
of American football games, even though this implementation of AR dates from the late 1990’s and makes very little money. If TV viewers don’t stop to think about it, they believe that the first down line is actually on the field. It moves with the field, not the TV screen, and it disappears behind players as they walk across it, just like the white yard lines that really are painted on the field. Similar technologies are used in TV broadcasts of other sports, sitcoms, and talk shows to add useful information or advertising to the TV video streams.
Examples of AR implementation that are more fashionable and better fit generally used definitions of AR are the iPhone app Star Walk and the Starbuck’s promotional app used around Valentine’s Day in 2012. Or the McDonald’s app currently used in Australia, which is probably the best mobile promotion using augmented reality created to date.
AR is, however, in its infancy, so a definition of AR needs to be broad enough to include more than what is available today.
If the augmentation is not seamless and dynamic, it’s not augmented reality. The provided information or stimulus should appear as part of reality, otherwise it’s not augmenting the reality. That’s clear enough, so that needs to be part of the definition.
The content can, of course, be computer generated, like the first down line or the images in the iPhone apps mentioned above, but it could also be any form of new content that does not already exist in the reality being perceived. Disney famously produced an AR event in New York City’s Times Square in which passers-by interacted with Disney characters (people in costumes, not computer generated images) that everyone in Times Square could see on giant monitors placed above the entrance to the Disney Store (no PC or mobile device required), but were actually in a studio outside Times Square. That’s clearly AR, so the definition needs to encompass such implementations.
Also, why restrict ourselves to PCs and mobile devices for delivery? The heads-up displays planned for near future generations of automobiles, like those on a modern fighter jet, are not exactly the sort of PC or mobile device envisioned in many definitions of AR, but most of us would agree that a heads-up display qualifies as augmented reality. The TVs used to see the yellow first down line are neither PCs nor mobile (for the most part). Any delivery mechanism is acceptable, as long as it results in an augmentation of reality.
Going a step further, why does AR have to be visual? Auditory information, for example, can be communicated through headphones. An app for blind people could provide street names and building numbers through a headset. Deaf people could be given a tactile sensation when a car honks or a siren approaches. At the other extreme, noise canceling head sets are, arguably, augmented reality devices because they change the perception of reality, in this case by reducing the perception of extraneous real sounds that interfere with perception of other sounds, real or artificially introduced, or simply a perception of quiet. Indeed, any sense could be subject to perceptual change. One can conceive of olfactory augmentation to alter the taste of food. A definition of augmented reality needs to encompass these ideas as well.
In the end, we’ve eliminated from common definitions of AR the restrictions imposed by requiring a) computer generated content, b) visual systems such as a camera, and c) a PC or a mobile device for delivery. We have maintained, however, AR’s tight connection with a) reality, b) the altered perception of reality, and c) the addition or removal of content. The better definition gives augmented reality researchers and product developers a broader and more accurate spectrum for innovation while maintaining the connection with existing products, services, and technologies. Augmented reality is the artificial, seamless, and dynamic integration of new content into, or removal of existing content from, perceptions of reality.