Vegetarianism is the practice of abstaining from the consumption of meat (red meat, poultry, seafood, insects, and the flesh of any other animal). It may also include abstaining from eating all by-products of animal slaughter. Vegetarianism may be adopted for various reasons. Many people object to eating meat out of respect for sentient animal life. Such ethical motivations have been codified under various religious beliefs as well as animal rights advocacy. Other motivations for vegetarianism are health-related, political, environmental, cultural, aesthetic, economic, taste-related, or relate to other personal preferences. There are many variations of the vegetarian diet: an ovo-lacto vegetarian diet includes both eggs and dairy products, an ovo-vegetarian diet includes eggs but not dairy products, and a lacto-vegetarian diet includes dairy products but not eggs. As the strictest of vegetarian diets, a vegan diet excludes all animal products, and can be accompanied by abstention from the use of animal-derived products, such as leather shoes. Maintenance of a vegetarian diet can be challenging. While avoidance of animal products may support health and ethical concerns, dietary supplements may be needed to prevent nutritional deficiency if all such products are shunned, particularly for vitamin B12. Packaged and processed foods may contain minor quantities of animal ingredients. While some vegetarians scrutinize product labels for such ingredients, others do not object to consuming them, or are unaware of their presence. Origin The first written use of the term "vegetarian" originated in the early 19th century, when authors referred to a vegetable regimen diet. Historically, 'vegetable' could be used to refer to any type of edible vegetation. Modern dictionaries explain its origin as a compound of vegetable (adjective) and the suffix -arian (in the sense of agrarian). The term was popularized with the foundation of the Vegetarian Society in Manchester in 1847, although it may have appeared in print before 1847. The earliest occurrences of the term seem to be related to Alcott House—a school on the north side of Ham Common, London—which was opened in July 1838 by James Pierrepont Greaves. From 1841, it was known as A Concordium, or Industry Harmony College, from which time the institution began to publish its own pamphlet entitled The Healthian, which provides some of the earliest appearances of the term "vegetarian". History The earliest record of vegetarianism comes from the 9th century BCE, inculcating tolerance towards all living beings. Parshwanatha and Mahavira, the 23rd and 24th tirthankaras