The standpoint from which a tale is conveyed is referred to as a point of view. In writing, three primary points of view are used: first person, second person, and third person. First person refers to the story being told by its protagonist; second person refers to commentary on the story by someone other than its protagonist; and third person refers to a story being told by a character who is not involved directly with the events, but can be inferred from context or observation. A point is defined as "a very small part" or "the amount that can be measured by a scale capable of measuring up to 100 grams": a point is exactly 0.001 gram. The term comes from the Latin ponuntia meaning "pointed stake or pin", referring to the tiny particles used for punctuation in printed books and today used as mathematical symbols. The atoma, or atom, was the smallest particle of an ancient Greek theory of matter. Today, we know it to be smaller - and therefore less relevant to human experience- than a proton, which has a mass about 1/1000th that of an atom. In mathematics, a point consists of a value, a property, or an element without dimension. In geometry, a point is any location where something could be placed or fixed, including a physical point such as a dot or a space between two things.