The official documentation is at: http://docs.alfresco.com
A store is a logical partition within the repository, grouped for a particular automated use. Each store contains a hierarchy of nodes with one root node.
Each store is identified by a content store reference. This reference consists of a store protocol (such as archive or workspace) and a store id (such as SpaceStore or User).
A node is a specialized object with properties and metadata. A node has hierarchical associations with other nodes to identify content and content spaces.
A space is just like a folder, but more: it can hold any type of content. Smart spaces are spaces with rules applied for automatic actions.
Can often can be thought of as a file or document made of two main elements: the content itself and information about the content (meta-data). E.g.: documents, video, audio, images, XML, HTML, ...
Types and Aspects
A node has one content type to define its class in the repository; such as content, space or custom object (wiki, forum etc). These types are defined in one of the content models of the repository.
A node contains zero or more aspects as the defined set for metadata indication. To extend the metadata definitions, aspects can be added freely to a node or its identifying node type. Afterwards, rules to act on the defined metadata can be applied to the repository content.
A node contains multiple properties, a set of manageable attribute values, defined according type and aspects. For example standard content properties in Alfresco are title, description, creator and modification date.
Actions and Rules
A unit of work that is performed on a node. Examples include adding an aspect, copying a node, or emailing notification.
A condition is a test applied to an action used to determine whether the action can be performed.
A composite action is a collection of actions that are combined in a designated order to make one unit of work. If any action within the composite fails, then no other actions within this composite are completed. The unit of work can be any size you determine.
A rule is a action or composite action with a rule type.
Every rule has a rule type and it characterizes the types of events in the repository that will cause the rule to be triggered. When a rule is triggered the composite action it represents is executed. A rule type is made up of a number of rule triggers.
A rule trigger relates to a repository policy and transforms the information acquired when that policy is fired into the information needed to trigger a rule.