Apollos was a first century apostle who was born as Jewish and later converted into Christianity. His name was mentioned several time in the New Testament. Apollos was a companion of Apostle Paul, and he played an important role in the founding of Ephesus Church.
We see the name of Apollos first in Acts 18:26;
He began to speak boldly in the synagogue; but when Priscilla and Aquila heard him, they took him aside and explained the Way of God to him more accurately.Acts 18:26
As we understand from this verse he was preaching about Jesus and his way, but he was not knowledgeable enough. So Priscilla and Aquila took him in and taught him about the way of Jesus Christ.
Then we see Apollos in the letter of Paul to Corinthians;
I planted, Apollos watered, but God gave the growth.1 Cor 3:6
And lastly we see Apollos mentioned in the Epistle to Titus by Apostle Paul;
Make every effort to send Zenas the lawyer and Apollos on their way, and see that they lack nothing.Titus 3:13