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: the 18th letter of the Greek alphabet — see Alphabet Table
: standard deviation
Recent Examples on the Web
These example sentences are selected automatically from various online news sources to reflect current usage of the word 'sigma.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.
1584, in the meaning defined at sense 1
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Resources for sigma
26 Sep 2018
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More Definitions for sigma
: the 18th letter of the Greek alphabet
See the full definition for sigma in the English Language Learners Dictionary
More from Merriam-Webster on sigma
See words that rhyme with sigma
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