In some situations, items can be dragged. The actual user can only drag words to stories, or inside a story to a different position.
An editor can drag any item to a different position in its collection. In addition, editors can drag items to a different collection. This usually means the item is moved to the new collection, not copied. This way, words can be dragged (moved) to another (sub)category. Subcategories can be dragged (moved) to another category. Top categories can be dragged (copied) to another vocabulary. Note: a top category will be copied instead of moved!