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om·i·cron | \ ˈä-mə-ˌkrän 
, ˈō-, British ō-ˈmī-(ˌ)krän \
, ˈō-, British ō-ˈmī-(ˌ)krän \Definition of omicron
: the 15th letter of the Greek alphabet — see Alphabet Table
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The first known use of omicron was in the 15th century
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