Being born in the Year of the Pig means the earthly branch of your birth year is 亥.
The Nature of This Branch
Hai water is a wide, gathered body of water. Where Zi moves, Hai holds — broad, undiscriminating in company, rich in imagination.
Your Sign Is One of Eight Characters
Your zodiac sign is the earthly branch of your birth year — one of the eight characters in a saju chart. The character that stands for you yourself is a different one: the day stem (日干).
Two people with the same sign can be entirely different if their other seven characters differ. What the year branch really speaks to is your roots, your early environment and the impression you give.