A novena is a nine day period of prayer (either private or public) to obtain special graces. The word novena is derived from the Latin word novem or nine. The biblical basis for this extended prayer comes from Acts 1:12-14 where the disciples "devoted themselves to prayer."
It is important during this time of the liturgical year because the Feast of Pentecost will be celebrated on Sunday, May 20, 2018.
The "first novena of the Church" is the Novena to the Holy Spirit.
Annual Pentecost Novena Begins May 11, 2018