1. <application> Any specific type of file produced or edited by a specific application; usually capable of being printed. E.g. "Word document", "Photoshop document", etc.
2. <hypertext> A term used on some systems (e.g. Intermedia) for a hypertext node. It is sometimes used for a collection of nodes on related topics, possibly stored or distributed as one.
3. <programming> To write documentation on a certain piece of code.