<human>:  What is the cultural significance of a Shamrock?
<bot>: A Shamrock is a symbol of national pride for the Irish and has been recognized since the 15th century. It is thought to be a symbol of hope, luck and faith, and its three leaves represent a Christian belief of the Father, Son and Holy Spirit. It is also a symbol of the struggle of the Irish against oppression and is widely used as a symbol of Irish heritage.