In mathematics the word sign refers to the property of being positive or negative. This is a glossary of math definitions for common and important mathematics terms used in arithmetic geometry and statistics. A real number less than zero.
Positive integers have values greater than zero.
Definition of Negative Reciprocal. Also can mean a number below some arbitrary reference point. So i to the fourth is the same thing as i to the zeroth power. Zero itself is neither negative nor positive.