Birthday

• POS: Noun
• HYPHEN: birth=day

CIDE DICTIONARY

Birthday, n. 

•  The day in which any person is born; day of origin or commencement.  [1913 Webster]

  "Those barbarous ages past, succeeded next
  The birthday of invention."  [1913 Webster]
•  The day of the month in which a person was born, in whatever succeeding year it may recur; the anniversary of one's birth.  [1913 Webster]

  "This is my birthday; as this very day
  Was Cassius born."  [1913 Webster]

Birthday, a. 

 Of or pertaining to the day of birth, or its anniversary; as, birthday gifts or festivities.  [1913 Webster]

OXFORD DICTIONARY

Birthday, n.
1 the day on which a person etc. was born.
2 the anniversary of this.

Idiom

birthday honours Brit. titles etc. given on a sovereign's official birthday. in one's birthday suit joc. naked.

THESAURUS

Birthday

anniversary, annual holiday, bicentenary, bicentennial, biennial, bissextile day, centenary, centennial, commemoration, decennial, diamond jubilee, golden wedding anniversary, holy days, immovable feast, jubilee, leap year, name day, natal day, octennial, quadrennial, quasquicentennial, quincentenary, quincentennial, quinquennial, septennial, sesquicentennial, sextennial, silver wedding anniversary, tercentenary, tercentennial, tricennial, triennial, wedding anniversary

ROGET THESAURUS

Birthday

Periodicity

N regularity of recurrence, periodicity, intermittence, beat, oscillation, pulse, pulsation, rhythm, alternation, alternateness, alternativeness, alternity, bout, round, revolution, rotation, turn, say, anniversary, jubilee, centenary, catamenia, courses, menses, menstrual flux, rota, cycle, period, stated time, routine, days of the week, Sunday, Monday, months of the year, January, feast, fast, Christmas, Easter, New Year's day, Allhallows, Allhallowmas, All Saints' Day, All Souls', All Souls' Day, Ash Wednesday, bicentennial, birthday, bissextile, Candlemas, Dewali, groundhog day, Halloween, Hallowmas, Lady day, leap year, Midsummer day, Muharram, woodchuck day, St. Swithin's day, natal day, yearbook, yuletide, punctuality, regularity, steadiness, periodic, periodical, serial, recurrent, cyclical, rhythmical, recurring, intermittent, remittent, alternate, every other, hourly, diurnal, daily, quotidian, tertian, weekly, hebdomadal, hebdomadary, biweekly, fortnightly, bimonthly, catamenial, monthly, menstrual, yearly, annual, biennial, triennial, centennial, secular, paschal, lenten, regular, steady, punctual, regular as clockwork, periodically, at regular intervals, at stated times, at fixed established, at established periods, punctually, de die in diem, from day to day, day by day, by turns, in turn, in rotation, alternately, every other day, off and on, ride and tie, round and round.