Public Name: This is the name that you are known by in public, and it embodies what you convey to the world at large. For example, Alphonse Capone preferred to abbreviate his first name, and was known to the public as "Al Capone". Similarly, George Smith Patton Jr. was most widely known as "George S. Patton". In contrast, Jennifer Love Hewitt (and her agent) are so pleased with her middle name that it is NEVER abbreviated.
Birth Name: This is the name you were born with, and that appears on your birth certificate. It is this name that determines your personal Rune, as well as playing a major part in your daily numerology readings. A good example of a birth name is Robert Allan Zimmerman, who bears the public name of "Bob Dylan", which he made one of the most legendary names in music.
Nickname: This is the name that friends or coworkers call you by, and embodies much of your private persona. It may be a shorter form of your first name, such as "Andy" for "Andrew", or it may be completely unrelated. For example, Halle Berry goes by "Hannah" among her friends. Similarly, the man whose birth name was Samuel Langhorne Clemens, better known by his public name of Mark Twain, bore the nickname of "Sam" amongst his friends.