Question: Why is there an “F” on the Green Dragon Mah Jongg Tile?

Answer: The “F” on the Green Dragon tiles stands for the word fa, which is actually fá cái and loosely translates to “get rich,” or “prosperity.”

The exact date of origin is unknown, but it’s believed that the meaning of the Green Dragon dates back to the Ming Dynasty. These Dragon tiles, known as honor suits, are often referred to as arrows or dragons. They symbolize an archer releasing their draw and convey the Confucian virtue of sincerity. Some even speculate that these symbols may have deeper connections to ancient Chinese philosophy, astrology, numerology, and their possible influence on the development of the occidental tarot.

Sources: MAH-JONGG from Shanghai to Miami Beach written by Christina Cavallaro and Anita Luu, TheMahjongtileset
ThoughtCo.