/ ˈdʒænjuəri; NAmE -jueri/ noun
[ U , C ] ( abbr. Jan. ) the 1st month of the year, between December and February.
HELP NOTE : To see how January is used, look at the examples at April .
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WORD ORIGIN
Old English , from Latin Januarius (mensis) (month) of Janus , the Roman god who presided over doors and beginnings.