Spanish omelette wheat tortilla of Mexico and neighbouring countries, which is a thin flatbread. In most of Hispanic America, where both the flatbread and potato omelette are eaten, the omelette is called "tortilla española" to distinguish it from the maize tortilla of the region. Because the potato is called "papa" in much of Hispanic America (instead of the term "patata" used in Spain), this dish can sometimes be referred to as "tortilla de papas" in that region as well. The Spanish tortilla ("tortilla de patatas" in Spain) is widely eaten in Spain and some Spanish-speaking countries. While there are numerous regional variations,
Active ingredient Active ingredient An active ingredient (AI) is the ingredient in a pharmaceutical drug or pesticide that is biologically active. The similar terms active pharmaceutical ingredient (API) and bulk active are also used in medicine, and the term active substance may be used for natural products. Some medication products may contain more than one active ingredient. The traditional word for the API is pharmacon or pharmakon (from , adapted from pharmacos) which originally denoted a magical substance or drug. The terms active constituent or active principle are often chosen when referring to the active substance of interest in a plant (such