"What's a node?" I asked myself when first using Drupal. "Isn't that the taxi station they drop passengers off in some sci-fi novel?". Well, close, but not in Drupal-speak. A node is the "techie terminology" used by Drupal (and Drupal developers) behind the scenes.
The easier term to understand is Content Type. It all started back in the days of Drupal 4.7 with a module called CCK. Drupal 5 was the version which saw more adoption of CCK than 4.7 and future versions of Drupal will likely eleminate the need for a separate module. Although, you'll always have the option to extend what type of content you can manage within your defined Content Types - using add-on modules.
