Q. Why do we break coconut?

A.  We all have seen it being done in all the poojas and sacred ceremonies. Coconut is broken at the inauguration of any project of significance.
The following is the significance:

Coconut represents our mind, thoughts, intellect and ego etc. These comprise ANTAHKARAN (Mano Buddhi Chitta) or the inner instrument. Body and senses etc. being the outer instrument. Fiber is the outer body etc. The EGO etc creates a barrier between our true self (Atma) and Ultimate self GOD (Paramatma).

Breaking of the coconut symbolizes the breaking of the ego. Once the ego is broken and offered to God as an offering the path is cleared for attainment of God.

The water inside the coconut represents our inner Sanskaras, vasanas etc and we offer them to God or in some traditions those are discarded after the coconut is broken.

The fruit is the mind etc that is offered to God, meaning it is made one pointed towards God. Krishna repeatedly says in Gita that devotee should make his mind and Buddhi (intellect) one pointed towards God and offer them to Him alone:

"Mai Arpit Manobudhi "
Mameva asya na sanshayam" ch 8 v 7

(Once you offer your mind and intellect to ME, you will attain ME , there is no doubt about that)

Therefore breaking and offering the coconut symbolizes "Breaking the ego, discarding the Vasanas and Sanskaras and offering the mind etc to God”.

It is very important that as we are performing the act we have our heart in it with full 100 % devotion an