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 as salicylic acid in willow bark or arecoline in areca nuts), because the word "ingredient" in many minds connotes a sense of human agency (that is, something that a person combines with other substances), whereas the natural products present in plants were not added by any human agency but rather occurred naturally ("a plant doesn't have ingredients"). In contrast with the active ingredients, the inactive ingredients are usually called excipients in pharmaceutical contexts. The main excipient that serves as a medium for conveying the active ingredient is usually called the vehicle. Petrolatum and mineral oil are common vehicles. The dosage