“Go” refers to the cows and “Pala” means protect. Lord Krishna was born in Mathura to Vasudeva and Devaki but was brought up by his foster parents, mother Yashoda and father Nanda who belonged to the cowherd clan of Brindavan. As Krishna grew up along with other boys of his age, he too tended lovingly to the cows, took them for grazing in the pastures and so on. Thus Gopala means the Lord who played the role of a cowherd. While this is the literal meaning, Baba has explained that Go means beings or souls or individuals.
So Gopala is he who tends the souls who fosters individuals, who keeps them away from harm, who strives to ensure that they remain in peace and happiness. He is the one who protects and provides. He is the one who enacted the role of a cowherd in the Dwapara age, the one who is constantly engaged in the welfare of individuals.