Public courses are just that, open to the general public. Anyone who can afford the green's fees can play on these courses. With these courses, there are no membership packages, you just pay to play.
Semi-PrivateSemi-Private golf courses are open to the public, but offer membership packages. Membership packages allow golfers to purchase a membership and avoid paying green's fees for the season.
PrivatePrivate courses are not open to the public. In order to play on these courses, golfers generally have to be a member or be invited by a member. Private courses occassionally allow guests during a "guest day", but are closed to the public the majority of the time.
ResortResort courses are located on resorts and are usually closed to the public. These courses are typically only playable to golfers staying at the resort.
MilitaryMilitary courses are located on military bases. These courses can be open or closed to the public.