Apocrypha is a plural word (singular: apocryphan) that originally denoted hidden or secret writings, to be read only by initiates into a given Christian group. It comes from Greek and is formed from the combination of apo (away) and krytein (hide or conceal). The word apocrypha, like many other words, has undergone a major change in meaning throughout the centuries. Concerning these ancient books, the word apocrypha originally meant a text too sacred and secret to be in everyone's hands. Christians today say that apocrypha are works, usually written, of unknown authorship or of doubtful origin. The word apocryphal (ἀπόκρυφος) was first applied to writings which were kept secret because they were the vehicles of esoteric knowledge considered too profound or too sacred to be disclosed to anyone other than the initiated. Apocrypha was applied to writings that were hidden not because of their divinity but because of their questionable value to the church. In general use, the word apocrypha came to mean "false, spurious, bad, or heretical."
Biblical apocrypha are a set of texts included in the Septuagint and Latin Vulgate but not in the Hebrew Bible. While Catholic tradition considers some of these texts to be deuterocanonical, Protestants consider them apocryphal. Thus, Protestant bibles do not include the books within the Old Testament but have sometimes included them in a separate section, usually called the Apocrypha. Other non-canonical apocryphal texts are generally called pseudepigrapha, a term that means "false attribution".