• In common usage positive is sometimes used in affirmation, as a synonym for "yes" or to express "certainty".
• In mathematics, a number is called positive if it is bigger than zero. See negative and non-negative numbers.
• In functional analysis, a bounded linear operator is positive if its spectrum consists of positive real numbers.
• In physics, one distinguishes positive and negative electric charges.
• In optics, converging lenses are also called positive lenses.
• If a medical test for a certain disease is applied, the outcome is termed positive if the disease is detected.
• In the humanities and social sciences, a theory is called positive if it aims to describe what is the case as opposed to what ought to be the case. See positive science.
• In philosophy, positivism is the name for theories which aim to be based on facts alone, eschewing metaphysics and religion.

See also "negative" and "normative."