Greek alphabet

=== In mathematics and science ===
{{Main|Greek letters used in mathematics, science, and engineering}}
Greek symbols are used as symbols in [[mathematics]], [[physics]] and other [[science]]s. Many symbols have traditional uses, such as lower case epsilon (ε) for [[Limit (mathematics)|an arbitrarily small positive number]], lower case pi (π) for the [[Pi|ratio of the circumference of a circle to its diameter]], capital sigma (Σ) for [[summation]], and lower case sigma (σ) for [[standard deviation]]. Formerly, the Greek letters were used for [[Tropical cyclone naming#North Atlantic Ocean|naming North Atlantic hurricanes]] if the normal list ran out. This happened only in the [[2005 Atlantic hurricane season|2005]] and [[2020 Atlantic hurricane season|2020]] hurricane seasons for a total of 15 storms, the last one being [[Hurricane Iota]]. However, this practice would be discontinued in 2021, citing the confusion many similar-sounding names caused. 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.<ref>{{Cite web|title=WHO announces simple, easy-to-say labels for SARS-CoV-2 Variants of Interest and Concern|url=https://www.who.int/news/item/31-05-2021-who-announces-simple-easy-to-say-labels-for-sars-cov-2-variants-of-interest-and-concern|access-date=2021-06-01|website=www.who.int|language=en}}</ref><ref>{{Cite web|date=2021-05-31|title=Covid-19 variants to be given Greek alphabet names to avoid stigma|url=http://www.theguardian.com/world/2021/jun/01/covid-19-variants-to-be-given-greek-alphabet-names-to-avoid-stigma|access-date=2021-06-01|website=the Guardian|language=en}}</ref>