The Sufi while in meditation invoke Hu to call forth the
OverSoul. Sufi Naajiy Zodok
Answer-2. Hu is a pronoun (Ism Zameer) suffixed to the name of
Almighty Allah making it 'Allah Hu' . It denotes that the Only
Authority is of Allah. It is repeated time and again during
meditation. Allah Hu, Allah Hu. Sometimes only Hu is sounded. It
also means the same.