A datum is a single fact. The word derives from the Latin dare, which means to give. In a sense, a datum is a given. When one starts to analyze a problem, specific data defines the problem.

The word information is derived from the Latin informare, meaning to give form or shape to or to teach. Information is much more than simply data. It is important and significant data.

Let us take an example. Suppose a business receives a water bill for $765. This is a single datum. In and of itself, it has little meaning. Suppose the bookkeeper checks the bill against that of the previous month and notes that it is twice the normal amount. This is significant. The bookkeeper now has information, namely that the water bill is sky-high. They might wonder if the water company made a mistake. Does the facility have a giant leak? The bookkeeper has no idea what to do.

When one finds oneself in a situation where one doesn’t know the right action to take or even how to proceed at all, one is missing knowledge.

Knowledge is the theoretical or practical understanding of a subject or situation that allows one to act in the best possible way.

In Old English and Latin, the word meant to acknowledge or recognize. When one has knowledge, one can act with certainty and take effective action. When one has only a vague idea about what to do, one has insufficient knowledge. Knowledge is learned behavior and is acquired through personal experience, books, manuals, or the experiences of others. It can be passed from one person to another.

In the water bill example, the bookkeeper might look at the bill carefully and notice the last payment was never received or perhaps was never sent. Alternatively, they might call the utility, which informs them that the company averages the monthly usage over a year to generate the monthly water bill and adjusts in January to make up for any shortfall. The bookkeeper now knows why January’s bill was so high and has gained knowledge. They also know what to expect in the future.

In summary, if one doesn’t know what to do, or what the correct action is, one is lacking the applicable knowledge. The solution is to discover what that knowledge is and learn it. It is even possible that the situation is so unique that knowledge about it doesn’t exist. In that case, one must discover it and one becomes a scientist, a researcher, or an inventor.