Inauguration Day, January 20 - the day designated for inauguration of the United States president

Gregorian calendar, New Style calendar - the solar calendar now in general use, introduced by Gregory XIII in 1582 to correct an error in the Julian calendar by suppressing 10 days, making Oct 5 be called Oct 15, and providing that only centenary years divisible by 400 should be leap years; it was adopted by Great Britain and the American colonies in 1752

New Year's, New Year's Day, January 1 - the first day of the year

Martin Luther King Day, Martin Luther King Jr's Birthday - observed on the Monday closest to January 15

Tet - the New Year in Vietnam; observed for three days after the first full moon after January 20th

January 20, Saint Agnes's Eve - a Christian holy day

Solemnity of Mary, January 1 - (Roman Catholic Church) a holy day of obligation

Epiphany of Our Lord, January 6, Three Kings' Day, Twelfth day, Epiphany - twelve days after Christmas; celebrates the visit of the three wise men to the infant Jesus

Twelfth night - eve of Twelfth day; evening of January 5

Christmas, Christmastide, Christmastime, Noel, Yule, Yuletide - period extending from Dec. 24 to Jan. 6

Gregorian calendar month - a month in the Gregorian calendar

mid-January - the middle part of January

winter, wintertime - the coldest season of the year; in the northern hemisphere it extends from the winter solstice to the vernal equinox