What is "pradyumna"

Pradyumna is the name of a character in the Srimad Bhagavatam. He was the son of Lord Krishna and Rukmini. Pradyumna is considered as one of the four vyuha avatar of Vishnu. According to some accounts, Pradyumna was an incarnation of Kama, the god of love. Pradyumna is also a name of the Hindu god Vishnu. He is one in 24 Keshava Namas (names), praised in all pujas. It is also the only name in Sanskrit with all the 3 letters joint (referred as जोडाक्षर)

The Harivamsa describes intricate relationships between Krishna Vasudeva, Sankarsana, Pradyumna and Aniruddha that would later form a Vaishnava concept of primary quadrupled expansion, or avatar.