Coconut is known as Shriphal in Hindu pujas and rituals. Coconut is considered pure and auspicious. It is also regarded as symbolic of Ganesha. In some regions banana is also considered as Shriphal.
Before any auspicious function or inauguration or even before using a car, a coconut is broken and offered.
Coconut is also offered as dakshina to priest, guru and elders.
Coconut is Shriphal because it has three eyes and the water and kernel in it is pure and untouched or polluted. So it is an ideal offering.
Another reason for choosing coconut as shriphal is because it is available 365 days and is not seasonal.