The difference is just language and translation:
1. Holy Ghost
- Older English term. "Ghost" used to mean "spirit" or "life force"
- You’ll see it a lot in the King James Version 1611: “...the Holy Ghost shall come upon thee” — Luke 1:35
- Still used today in some churches and songs because it sounds traditional
2. Holy Spirit
- More modern English translation
- Used in newer Bible versions like NIV, ESV, NLT: “...the Holy Spirit will come on you” — Luke 1:35
- "Spirit" is closer to the original Greek word Pneuma and Hebrew Ruach, which both mean breath, wind, spirit
Same role in the Bible:
- 3rd person of the Trinity: God the Father, God the Son Jesus, God the Holy Spirit/Ghost
- Comforter, Teacher, Helper, the one who lives in believers — John 14:26
- Gives gifts, convicts, guides, empowers
So if someone says "Holy Ghost" and someone else says "Holy Spirit", they’re talking about the same God.
Some Pentecostal and older denominations prefer "Holy Ghost". Most newer churches and Bible translations use "Holy Spirit".