The Chinese word for gourd, Hulu, has many auspicious associations.  In some dialects, the character hu has a similar pronounciation to fu which means "happiness" or "good fortune".  Therefore, saying hulu for gourd would sound similar to fulu which means "happiness and high position".

The number "8" is the most favourite number of the Chinese.  The Cantonese pronounciation for this number is "Fatt" which means "to prosper".  Since the shape of the gourd resembles "8", the gourd is regarded as an auspicious object.