Training Instructor: Ground and/or Simulator instructor. Cannot give check rides.
Simulator Check Airman: Can give annual Proficiency Checks.
DE (Designated Examinrer) or TCE (Training Center Examiner): Can give ATP and Type Ratings in the simulator.
Line Check Airman: Can give annual line checks in the airplane, as well as OE and IOE.
IOE (Initial Operating Experience): Initial flights in an airplane type at an airline under supervision of a Line Check Airman.
OE (Operating Experience): Initial flights in an airplane as a Captain under supervision of a Line Check Airman. IOE and OE are ~25 hours and/or 6-8 segments.