Dhāraṇī [-] mystical incantation. The verbal meaning of the word Dhāraṇī is that which holds. It is a magical formula in the form of a mantra in Sanskrit. The mystic mantra has a potential to hold the Buddha's teachings in the heart of him who recites. It is recited in order to attain mindfulness (smṛti), power (bala) and wisdom (prajñā). Its recitation brings in good luck such as a long life, victory, protection from snakes and removes evils such as disease.     The Dhāraṇī mantra-s are used for threefold purpose, namely, incantation, benediction and magic spell. Dhāraṇī mantra-s are prevalent in the tantric Buddhism in Tibet, and in the Shingon Sect of Buddhism in Japan. Since Dhāraṇī-s are based on the occult power of sound, they do not have any verbal meaning. They contain 'seed syllable' (bīja).     The later Mahāyāna literature contains Dhāraṇī-s. The Prajñā Pāramitā Hṛdaya Sūtra-s are used as Dhāraṇī-s. In the 9th chapter of Suvarṇaprabhāsa -- a later Mahāyāna Sūtra, Śrī Mahādevī -- the great goddess glorifies the Suvarṇaprabhāsa as a Dhāraṇī. Thus the Dhāraṇī-s often form part of the Mahāyāna Sūtra-s. However, independent works on Dhāraṇī-s such as large collections of Dhāraṇī-s are also found. The Dhāraṇī-mantra-saṃgraha is a collection of Dhāraṇī-s.     The Pañcarakṣā, that is, the collection of the five Dhāraṇī-s is popular in Nepal. These five protecting spells include

(1) mahā-pratisarā (for protection against sin, disease and evils),
(2) mahā-sahasrapramardinī (for protection against evil spirits),
(3) mahā-māyūrī or vidyārājñī (for protection against snake-poison),
(4) mahā-śītavatī (for protection against 'cruel' planets, cruel animals and poisonous insects), and
(5) mahā rakṣā mantrānusāriṇī (for protection against diseases).

Mahāyāna-Sūtrālaṅkāra. XVIII. 141. Saddharmapuṇḍarīkasūtram. XXI. 496-502. Suvarṇaprabhāsasūtra. IX. 60-62; X. 63.

Buddhānusmṛti - A Glossary of Buddhist Terms

dhāraṇī

(Sanskrit). The term literally means ‘retention’ and refers to high levels of mindfulness (smṛti) and insight (prajñā) derived from spiritual practice. In early Mahāyāna Buddhism, four categories were distinguished: the retention of patience (kṣānti-dhāraṇī), the retention of mantra (mantra-dhāraṇī), the retention of words (pada-dhāraṇī), and the retention of meaning (artha-dhāraṇī). Mantra-dhāraṇīs were a mnemonic form of mantra designed to facilitate the retention of various teachings, often considered to be a summary version of long sūtras. Later, with the rise of tantric Buddhism, dhāraṇīs became indistinguishable from mantras in general though they are generally of greater length than ordinary mantras and can largely be understood as normal speech.

A Dictionary of Buddhism, Oxford University Press, 2003, 2004 (which is available in electronic version from answer.com)