The fruit of Capsicum plants have a variety of names depending on place and type. The piquant (spicy) variety are commonly called chili peppers, or simply "chilies". The large mild form is called red pepper, green pepper or bell pepper in North America, sweet pepper in Britain, and typically just "capsicum" in Australia, New Zealand, and India. The fruit is called paprika in some other countries (although paprika can also refer to the powdered spice made from various capsicum fruit).
The generic name is derived from the Greek word κάπτω (kapto), meaning "to bite" or "to swallow." The name "pepper" came into use because of their similar flavour to the condiment black pepper, Piper nigrum, although there is no botanical relationship with this plant, or with Sichuan pepper. The original Mexican term, chilli (now chile in Mexico) came from the Nahuatl word chilli or xilli, referring to a larger Capsicum variety cultivated at least since 3000 BC, as evidenced by remains found in pottery from Puebla and Oaxaca.
Read more about Capsicum: Capsaicin in Capsicum, Cuisine, Species and Varieties, Synonyms and Common Names, Pictures of Capsicum Cultivars