Dimension? Fact? What the ... ?

How to explain what is a Dimension and a Fact in human language.

That beep theory

Remember when you are buying one item in a grocery store and that precise moment when the laser read the item's bar code and the sound heard... "beep".

Stop the time and think, what is really happening ?

Basically, a lot of data comes alive, data related to the second of a minute of an hour, day, month, year, your name, phone number, gender, the place where you are buying and the product.

If we were able to group that information in a logical way we will find something like this:

Information about Time: second, minute, hour, day, month, year.
Information about Customer: name, phone number, gender.
Information about Geography: city, state, country.
Information about Product: code, name, provider and price and discount.

All that information which describes how the transaction, trade or a business was made will be called business aspects, and all the information about the cost, effort or other quantifiable data will be called business measures.

Business aspects describes the characteristics of a transaction, and will be stored in tables named Dimensions. For our example: Time Dimension, Customer Dimension, Geography Dimension, and Product Dimension.

Business measures implies what was the cost of the transaction, and will be stored in a table named Facts, so we will have Price and Discount.

So, if you want to know how much was the sales in 2012, just sum the price (from Facts)
of the products sell on the year 2012 (from Time Dimension)

... To think about:

Easiest way to explain this concepts to client. At least they will know what are paying for. Don´t they?