The correct spelling of the word is "Pentecost," not "Pentecosty." The pronunciation of this word is /ˈpɛntɪˌkɒst/. The word is derived from the Greek word "pentēkostē," which means "fiftieth." It is a Christian holiday that occurs fifty days after Easter and celebrates the descent of the Holy Spirit upon the apostles. The incorrect spelling may be due to a misunderstanding of the pronunciation or confusion with the word "ecstasy." It is important to use correct spelling when communicating to ensure clear and effective communication.