Bayram is the Turkic word for a nationally-celebrated festival or holiday, applicable to both national (i.e. secular) and religious celebrations.
Likely owing to the enduring Ottoman Turkish influence in the Balkans and parts of South-Eastern Europe, many non-Turkish peoples like Romanians, Bosniaks, Albanian Muslims, Gorani people, Pomaks as well as Muslims from the Northern Caucasus such as Chechens, Avars, Ingush and Muslims from Azerbaijan, Crimea and other Turkic peoples, have similarly adopted the use of the word "Bayram", using the term "Lesser Bairam" to refer to their own Eid al-Fitr celebrations; "Greater Bairam" refers to Eid al Adha.[1]
State holidays in Turkey have set dates under the nationally-used Gregorian Calendar, while the Islamic religious holidays are coordinated and publicly announced in advance by the Government's Presidency of Religious Affairs department according to the Lunar Calendar, and are subsequently accommodated into the national Gregorian Calendar, which results in the dates for religious holidays changing every year with a shift margin of approximately 11 days.
Large scale non-Turkish or non-Islamic traditions and celebrations may similarly be called Bayram. Halloween is called "Cadılar Bayramı" ("Bayram of Witches"), Easter is "Paskalya Bayramı" ("Easter Bayram"), Christmas is "Noel Bayramı" ("Christmas Bayram"), Passover is "Hamursuz Bayramı" ("No-dough Bayram"), and Hanukkah is "Yeniden Adanma Bayramı" ("Renewal" or "Rededication Bayram"). Not every special occasion or holiday is referred to as a Bayram; those that are not include World Health Day, and Liberation of Istanbul, among others.[2]
Former national festival
(The dictionary data base on the TDK site based on: Divanü Lugati't-Türk ("Compendium of the languages of the Turks") of Mahmud al-Kashgari, 1072–1074)