True Course, Magnetic Course, Magnetic Heading, Compass Heading
1) True Course (TC): This is the course measured from your navigation plotter when you plot your flight on your map.
2) True Heading (TH): True course corrected for the winds aloft. Use an E6B or similar flight computer and the forecast winds aloft to correct your true course to determine a true heading. Remember, Forecast Winds are given as true.
3) Magnetic Heading (MH): The difference between true north and magnetic north is known as variation. Lines of variation are shown on a sectional chart as dashed magenta lines and called isogonic lines. By adding or subtracting variation from your true heading you will get your magnetic heading.
4) Compass Heading (CH): Items from inside the airplane can actually affect the performance of the compass. Aircraft technicians take account for this and will place a placard beneath the compass displaying the errors for certain headings. These errors are referred to as deviation. By adding or subtracting deviation from your magnetic heading this will give you a compass heading. A compass heading is the direction you will turn the aircraft to that has been corrected for winds, variation and deviation. In an ideal world, this would have you following your true course perfectly that you had plotted earlier on the map.
So in review:
Course: Is always the line drawn on the chart
Heading: The direction which the airplane is pointed