Answer: Prayer is an offering up of our desires unto God₁, in the name of Christ₂, by the help of his Spirit₃; with confession of our sins_4, and thankful acknowledgment of his mercies₅.

1. Psalm 62:8
2. John 16:23
3. Romans 8:26
4. Psalm 32:5-6; Dan 9:4
5. Phil 4:6

For further study see:

1. WSC 98:  What is prayer?