A crypt is a room under a church, often of stone, that in the past was used for burying people. You go down steps from the church floor and find a cool, dim space with tombs or shelves for the dead. Some crypts are still visited; some hold the bones of important people. The word is old and a little solemn. Though actually, English took it from Latin crypta, a vault, and that came from a Greek word meaning hidden — so a crypt is a hidden room. That same hidden idea shows up in cryptic, a message that hides its meaning, and in encrypt, to hide writing. A crypt is not the same as a cellar under a house, and it is not crypto as in cryptocurrency; that short form is slang from cryptography, the art of secret codes. Here we mean the burial room under a church.