Definition: The term "sifr" comes from the Hebrew word "sefira," which means "the secret." It's a Hebrew verb, literally meaning to be hidden or kept secret, often referring to some spiritual or personal knowledge or secrets. In the Bible, "sifr" refers to the ancient Hebrew words for the Book of Revelation and the Apocalypse of St. John, which are believed to contain the last book of the Old Testament. This book contains messages from God, including verses that could potentially be used as a guide or prophecy concerning events that have yet to happen.