Categories are how we recognise, differentiate, group and understand different things.

We do this all the time in our daily lives. For instance we categorise foods into what we like and don't like. We categorise things in our in-tray as urgent, not so urgent, do it tomorrow or forget. We categorise experiences as good or bad. 

There are many ways of categorising things.

We can create hierachcical structures for our categories. These are called taxonomies. Or we can create flat single levels of categories - in other words just a list of terms.

The problem with categorisation is that people have different concepts ogf how things should be categorised. For example a child's view of a taxonomy for cars might be Size, Colour, Shape, Speed. An adults might be Fuel economy, Number of Seats, Engine Size and so on.

Linking to a category

Suppose you have categorised a load of stories and you want to link to them and display them as a listing?

All you do is go to Administer>Content Management>Categories>List

This
lists the Vocabularies. Click the 'list terms' link on the vocabulary
you are using. This shows all the terms in the vocabulary. Hover your
mouse over the term you wish to use and the link shos up in the Status
Bar of your browser. (The Status Bar is usually right at the bottom of
your browser window.)

The link follows the pattern http://ww.mysite.com/taxonomy/term/3

Paste in the taxonomy/term/3 part of the path and this will ceate your listing.

Linking to more than one category

Imagine you have two different categories and you want a single menu item that will list them both.

All you need to do is go to the list of term and pick up the taxonomy term IDs.

Vocabularies help us to organise our category terms.

Vocabularies are a collections of words - or Terms as they are called in Drupal - that we use to organise content of a similar type.

Categories are synonymous with Terms. In other words if I create the term 'Red' then Red is a category I can put content into. You will get used to this when you start creating your taxonomic system.

Example of a vocabulary use

We might create the following terms to categorise car engine size

• less than 1000cc
• 1000-1200cc
• 1200-1800
• more than 1800

We can collect these terms into a vocabulary called Cars along with many other terms we associate with cars.

We can create another vocabulary called Books and put the following terms into it