The dried, unripe berries (peppercorns) of the Piper nigrum plant which are commonly used as a spice and seasoning. They are either used whole, or in a ground or crushed form.
The plant Piper nigrum.
Any fruit of a plant of the botanical genus Capsicum, which has a spicy/burning flavour because it contains capsaicin. (Not all chili peppers are particularly spicy, but all true chili peppers contain some capsaicin, in contrast to e.g. the bell pepper, which is not a true chili pepper and does not.)