Definition - What does Agni Mandala mean?
Agni mandala can have two different meanings in Buddhism and Hinduism. There is the literal translation from Sanskrit with agni meaning "fire" and mandala being a term for a geometric design, often circular, that symbolizes the universe; therefore, agni mandala may be called "sphere of fire" in English. The second definition is in regards to Kundalini yoga and the energy flow of kundalini through the yogi's chakras.
Yogapedia explains Agni Mandala
The mandala is a treasured shape in the Hindu and Buddhist religions. Mandalas that are created to pay homage to agni (fire) are brightly colored to resemble fire and used in ceremonies for energy flow and rebirth.
Agni mandala can also be a term used for the symbolic journey that kundalini -- personified as Agni Mandala Vasini -- makes through the subtle body. This mother figure starts coiled at the lowest chakra point, the muladhara, which is located near the pelvis and tailbone. As the yogi meditates on the chakras or chants to activate their energy, kundalini uncoils and journeys from the pelvis to the top of the head. Her final resting place is the seventh chakra, the sahasrara, which is located on the crown of the head. Once she reaches the top, she can unite with the higher power or universe. This journey through the body known as agni mandala, and the unification with the universe, can lead to enlightenment for the yogi.