Prayer

Webster

1 a (1) : an address (as a petition) to God or a god in word or thought
    (2) : a set order of words used in praying
  b : an earnest request or wish
2 : the act or practice of praying to God or a god

Historical

chanting, meditation, physical suffering, noisy

Spirit

Romans 8

26 Likewise the Spirit also helpeth our infirmities: for we know not what we should pray for as we ought: but the Spirit itself maketh intercession for us with groanings which cannot be uttered.
27 And he that searcheth the hearts knoweth what is the mind of the Spirit, because he maketh intercession for the saints according to the will of God.
28 And we know that all things work together for good to them that love God, to them who are the called according to his purpose.

1 Corinthians 14
14 For if I pray in an unknown tongue, my spirit prayeth, but my understanding is unfruitful.
15 What is it then? I will pray with the spirit, and I will pray with the understanding also: I will sing with the spirit, and I will sing with the understanding also.

Ephesians 6
18 Praying always with all prayer and supplication in the Spirit, and watching thereunto with all perseverance and supplication for all saints;

Supplication

1 : to ask humbly and earnestly of
2 : to ask for earnestly and humbly