Difference between retain sample and stability sample

Dear team,
What is difference between retain sample and stability sample???

Retention or retain sample: a sample of a fully packaged unit from EACH batch of finished product. It is stored for identification or testing purposes. For example, presentation, packaging, labelling, patient information leaflet, batch number, expiry date or purity, assay etc should the need arise during the shelf life of the batch concerned (customer complaints etc).
Stability sample: sample taken a from a batch used for stability testing of a product. After production a number of packaged product is stored under predetermined conditions and samples of this product are tested at predetermined time points to determine the shelf life of said product in its final packaging.