set of natural numbers in set theory (although or N is more common in other areas of mathematics) an asymptotic dominant notation related to big O notation in probability theory, a possible outcome of an experiment the arithmetic function counting a number's distinct prime factors the symbol ϖ, a graphic variant of π, is sometimes construed as omega with a bar over it; see π the unsaturated fats nomenclature in biochemistry (e.g. ω−3 fatty acids) the first uncountable ordinal (also written as Ω) the clique number (number of vertices in a maximum clique) of a graph in graph theory See also Blackboard bold letters used in mathematics English pronunciation of Greek letters List of mathematical uses of Latin letters List of letters used in mathematics and science Glossary of mathematical symbols Mathematical Alphanumeric Symbols (a Unicode block) Mathematical notation References External links A pronunciation guide with audio Greek alphabet letters onclick copy paste