Source:http://linkedlifedata.com/resource/umls/id/C1705273
NCI: A symbol or mathematical function that represents a specific action. For example, a plus sign (+) is an operator that represents addition. The basic mathematic operators are + addition, - subtraction,* multiplication,/ division. In addition to these operators, many programs and programming languages recognize other operators that allow you to manipulate numbers and text in more sophisticated ways. For example, Boolean operators enable you to test the truth or falsity of conditions, and relational operators let you compare one value to another. (from pcwebopaedia.com)