Dhi

Dhi: The mind's ability to learn or acquire knowledge.
Dhriti: The mind's ability to process and store what it has learned.
Dhyana: Meditation. The seventh limb of the Ashtanga or Raja Yoga system.

Samādhi is the mental discipline required to develop mastery over one's own mind. This is done through the practice of various contemplative and meditative practices, and includes: ...

Âdhi: place, situation, (see l o k a).
Âdityas: the twelve demigod sons of A d i t i.

Samâdhi-Yoga: The yoga ecstasy or eternal bliss
Sâmkhya-Yoga: The discipline of insight, a reference of which is found in the Mahâbhârata ...

Vedic literature is replete with references to prayerful contemplation'; (Brahman), higher vision; (dhi), and; the ideal harmony; (rita). Vedic people relied on rishis (dedicated Vedic Yogis) to teach them how to live in divine harmony.

The Sanskrit word for meditation is Dhyana, which comes from the verbal root dhi or dhya. Both roots mean to "think", this is particularly true in the sense of inquiry, examination or introspection.

by the ancient sage Manu, prescribes ten essential rules for the observance of dharma: Patience (dhriti), forgiveness (kshama), piety or self control (dama), non-stealing (asteya), sanctity (shauch), control of senses (indraiya-nigrah), reason (dhi), ...

See also: Mind, Vedic, Body, Yoga, Meditation