There is a quote attributed to George Bernard Shaw that follows along the lines "Britain and America are two nations divided by a common language". Whether or not the attribution is or isn't Shaw's, the point is that even though we use the same words, those words can (and often do) have quite distinctly different meanings because of our cultural differences1. There's even a British English vs. American English translation dictionary2!
To put it short and sweet - words, the terms we use, do not have one correct meaning.
Words can mean different things at different times. They come into existence to express thoughts by a group of people that share them, at a point in time, with a mean-ing that reflects their origin, use, and timeframe. Take, for instance, the word awful. Originally, that word meant "worthy of awe", as in "very inspiring". However, over time it has come to mean bad, displeasing, offensive, etc. A quick Google search will produce list upon list of terms that have changed over time3.
More specifically, the words and phrases that you find in a dictionary exist to express these shared thoughts, which we'll refer to as concepts throughout this document. We won't go into the philosophical debate of whether concepts define words or do words define concepts, a debate that is currently plaguing educators today4, as it has been since the times of Plato and Socrates5. Nor will we spend time debating about specific definitions of terms, how the definitions morph over time, or the nature of, and demands on, definitions6.
Instead this document will focus on how to fulfill the need to establish and maintain definitions for specific terms within specific subject fields7. There is an entire international standard dedicated this pursuit8, which we have drawn much of our inspiration from.
The issue we are attempting to remedy in this document, is the tendency of each subject field to create its own sub-language of specific terms and their definitions. These terms might be shared with other subject fields, but quite often the definitions for these shared terms are different. And just as often, those in specific subject fields create new, distinct terms used to describe the same concept as other terms found in other subject fields. So, we end up with this:
Same words - different definitions.
Same definitions - different words.
If you want a real-word example, perform this Google search:
what is personally identifiable information?
The last time we performed this search, Google returned over 1.7 million entries with well over 100 definitions (we stopped counting about then)9. With this huuuuuuge list of potential definitions for a key term such as Personally Identifiable Information, you have to agree with us that the only way you can share your meaning is through how you use the term, and better yet, if you can provide a definition for the key terms you are using.
In short, if you define your key terms, you'll clarify the concepts behind the terms you are using in that argument, in that document you wrote, or if they are added to some custom dictionary, in that specific field the dictionary covers.