A Name-Value Pair is common method of organizing information in a computer.
The Name portion of a Name-Value Pair is what is being described. It can also be described as a label.
The Value is the actual description.
In short, the Name gives the value its meaning.
An example will best explain Name-Value Pairs. In this case, the following describes a product using Name-Value Pairs:
Title: Hungry Dog Chow Price: $5.99 Product Code: HDC-4453 Quantity In Stock: 23 Product URL: http://www.hungrydogchow.com/product.asp?id=451232
Now, the Names above are: Title, Price, Product Code, Quantity In Stock, Description, and Product URL.
Each of these has a value, making a pair: Hungry Dog Chow, $5.99, HDC-4453, etc.
Obviously, with the Name of Price, you know that $5.99 is how much Hungry Dog Chow costs.
The flexibility of Name-Value Pairs are the core of why they are useful when communicating on the internet.