The level where the category fits in the site's category hierarchy. For example, if this field has a value of 2, then the category is 2 levels below the root category.
Note that the value of CategoryLevel will always be 1 level below the level of the requested category. To retrieve a category's children, pass its CategoryID back into the request.
In the FindItemsAdvanced response, ItemCount indicates the total quantity of matching items in the category.
In the FindItemsAdvanced response, sibling categories (i.e., matching categories at the same level) are sorted by ItemCount, descending order.
See the
Field Index to learn which calls use CategoryLevel.