section_path: Other uses/In mathematics and science
section_name: In mathematics and science
paragraph_text: In mathematics and science
  
  Greek symbols are used as symbols in mathematics, physics and other sciences. Many symbols have traditional uses, such as lower case epsilon (ε) for an arbitrarily small positive number, lower case pi (π) for the ratio of the circumference of a circle to its diameter, capital sigma (Σ) for summation, and lower case sigma (σ) for standard deviation. For many years the Greek alphabet was used by the World Meteorological Organization for naming North Atlantic hurricanes if a season was so active that it exhausted the regular list of storm names. This happened during the 2005 season (when Alpha through Zeta were used), and the 2020 season (when Alpha through Iota were used), after which the practice was discontinued. In May 2021 the World Health Organization announced that the variants of SARS-CoV-2 of the virus would be named using letters of the Greek alphabet to avoid stigma and simplify communications for non-scientific audiences.