A component is the smallest block of content that editors can edit, delete and move as a single unit on the page. At its simplest a component may be just text. However, a component can contain almost anything: a related image, a list of links or a teaser to another page. In the STK, Magnolia provides ready-made components for common use cases such as and content and . Component definitions are configured in STK > Template Definitions
Other components are supplied by specific modules. You can find their template definitions and associated dialog definitions in the Configuration app >
/modules/<module name>/templates/components and
Note that same or similar components can be found in both the STK and specific modules, such as the Public User Registration module.
This is a complete reference of Standard Templating Kit components and key components provided by other modules.