Krishna, the meaning of the word in Sanskrit is all-attractive.
He is the Supreme Personality of Godhead, also called as God of gods. In other words, Krishna is the Godhead because He is all-attractive.
From practical experience we can observe that one is attractive due to (1) Wealth, (2) Power, (3) Fame, (4) Beauty, (5) Wisdom and (6) Renunciation
One who is in possession of all six of these opulences at the same time and who possesses them to an unlimited degree is understood to be the Supreme Personality of Godhead according to Parasara Muni a great Vedic authority.
Krishna is the principal protagonist with Arjuna in the Bhagavad Gita also known as the Song of God, which depicts the conversation between the Royal Prince Arjuna and Krishna during the great battle of Kurukshetra 5000 years ago where Arjuna discovers that Krishna is God and then comprehends his nature and will for him and for mankind. In the present age Krishna is one of the most widely revered and most popular of all Indian divinities.