The Holy Ghost (usually called the Holy Spirit) is the third part of the Godhead (or Trinity).
The King James translation of the Bible (circa 1611) uses the phrase Holy Ghost, whereas most other translations use Holy Spirit.
Key verse about Holy Ghost: “But the Comforter, which is the Holy Ghost, whom the Father will send in my name, he shall teach you all things, and bring all things to your remembrance, whatsoever I have said unto you” (John 14:26, KJV).
A lifelong student of the Bible, Peter DeHaan, PhD, wrote the 1,000-page website ABibleADay.com to encourage people to explore the Bible. His main blog and many books urge Christians to push past the status quo and reconsider how they practice their faith in every area of their lives.