An orison is a prayer or plea to a deity. You might make an orison if you wanted your sick mom to get better.
Some words are considered archaic — meaning they are not in common modern use. Such a word is orison, which means a prayer. Today, you'd be surprised to see the word outside of a poem or some liturgical reference. This comes from a Latin word meaning to speak, and it means to speak to God. It's a poetic word Shakespeare used in Romeo and Juliet, when Juliet says, "I have need of many orisons" as she prepares to deceive her parents.