Component : an ACS component is made with zero, one or more little parts of SPIP templates with an administration user interface.
Models : an ACS model is a SPIP templates set (a templates directory) with ACS components.
Nut : a nut is a small SPIP template part.
Pencil : little icon of a pencil to edit components from public pages of the website.
Template : pages are made from templates which formats contents read in database.