noun🔗ShareThe eighteenth letter of the Classical and Modern Greek alphabets, the twentieth letter of Old and Ancient."In Greek class, we learned that sigma is the eighteenth letter of the alphabet. "languagewritingsignChat with AIVocabulary GamePractice Reading
noun🔗ShareThe symbol Σ, used to indicate summation of a set or series."The math textbook explained how to use the sigma notation (Σ) to easily represent the sum of many numbers in a sequence. "mathnumbersignstatisticsChat with AIVocabulary GamePractice Reading
noun🔗ShareThe symbol σ, used to indicate one standard deviation from the mean, particularly in a normal distribution."The teacher explained that a score one sigma above the mean in the math test meant the student performed better than most of the class. "mathstatisticsChat with AIVocabulary GamePractice Reading
