We will frequently use five different names for elements of planning and managing activities. so it is worth getting to know them:

• Activity - a general name for something that you intend to do. Specifically, an Activity will be one of the four different types listed below.
   
• Project - a set of related Activities that are focused towards an outcome.
   
• Result - an intermediate step within a project, that has a defined outcome or something that is delivered. Project Managers would recognise these as "milestones" and "GTD" users as "Subprojects".
   
  If you prefer to use the term "Subproject", there is a setting in the  ResultsManager tab | Options group | Options | ResultsManager Options  dialogue to select this. (Power User mode only).
   
• Action - a step in a project that creates progress
   
• Next Action - a particular type of Action that is ready to be done. Next Actions are not waiting for anything else to happen, and can be started straight away.

Some of the other terms are listed in Appendix A, but those listed above are the basic ones that are used frequently.