There are different levels of packaging that a consumer may be exposed to. Usually, the customer is handling the product in its primary packaging. This is the packaging that the product is seen in as it sits on the store shelf for example.
The primary packaging is the packaging that is exposed to the consumer and so will have the attributes conveying important information to the consumer. However, the overall packaging can also be subdivided into other levels of packaging.
The first level of packaging is the package that the product is contained in. This level of packaging may be the one that the consumer sees, but depending on the product, the first level package may be as simple as a clear plastic bag. For example, in a cereal box, the box is displayed to the consumer, however the actual cereal is contained within a sealed plastic bag. The bag is the first level of packaging.
The next, or second level of packaging in this example would be the cereal box itself. In this case, the first level of packaging provides some protection to the food item and conveys no information to the consumer. The cereal box however, acting as the second level, provides additional protection, bt it also provides information to the consumer, as well as a way for the cereal to be displayed, i.e. a box will fit better on a shelf than a plastic bag full of cereal.
Food for thought, did you ever wonder why cereal is contained within a plastic bag and then put into a box, whereas pasta or potato chips are only packaging with only one level of packaging?
Sometimes both levels of packaging will provide information to the consumer. Take for example a bottle of aspirin. You can often find aspirin packaged within the first level bottle, and a second level box.
A product may even have a third level pacakge. Products that are sold in bulk items can often have a third level. The same cereal box sold in a bulk store may be sold in a larger box which contains two or three smaller boxes, which contains a plastic bag.
Every level of packaging is very important and every aspect of it should be closely considered to convey not only its protective value to the product but as a way to communicate to the consumer.