Long weekend is a term used in Western countries to denote a weekend that is at least three days long (so, a "three-day weekend"), due to a holiday falling on either the Friday or Monday.
Most countries (although notably not the USA) also feature many "four-day weekends," in which two days adjoining the weekend are holidays. (Examples can include Easter Monday / Good Friday, and Christmas Day / Boxing Day.)
Further, in many nations, when a lone holiday occurs on a Tuesday or a Thursday, the gap between that day and the weekend may also be designated as a holiday, or set to be a movable or floating holiday, or indeed work/school may be avoided by consensus unofficially. This is typically referred to by a phrase involving "bridge" in most languages.
A special situation exists in France in some elementary schools, where there is no school on Wednesday: thus, any four-day weekend is essentially a "five-day weekend" for the kids and their teachers. Any four-day bridge, for example: Thursday (Holiday) and Friday (bridge day) for Ascension, is essentially a "five-day weekend" to some teachers.
Four-day "bridge" weekends are commonplace in non-English speaking countries, but there are only a couple of examples in English-speaking countries:
In the USA, the fourth Thursday of November is Thanksgiving; but the adjacent Friday is made in to a non-working day at some businesses. In Melbourne, Australia, the Melbourne Cup holiday is a Tuesday, but very many people modify their work arrangements to have the Monday off. NextLongWeekend.com displays the upcoming long weekends in USA, Australia, Canada and United Kingdom.
The term for a four-day weekend in some Spanish-speaking countries is puente ("bridge") or simply "fin de semana largo".
In Spain, the "bridge" becomes an "aqueduct" in some years when the anniversary of the Spanish Constitution of 1978 (December 6) and the Blessed Virgin Mary's Immaculate Conception (December 8) and a weekend plus a movable holiday form a block of five days.
France uses the same "bridge" idiom: faire le pont (literally meaning simply "make the bridge") is the universal phrase used to mean taking additional holiday days, to make an "even longer" holiday. Remembering that in France there is no school on Wednesdays, this can lead to very long "weekends" indeed. For example, if there is already an official holiday on Thursday/Friday, one could "faire le pont" on the following Monday/Tuesday - leading to an "eight-day weekend" (Wednesday through Wednesday inclusive).
The Italians and Portuguese do the same with their cognates ponte."
In Slovenian, the term podaljšan vikend ("prolonged weekend") is used for a three-day weekend. Four-day weekends also happen quite frequently, because January 1 and January 2 are public holidays (both New Year Day), as well as May 1 and May 2 (both May Day). A peculiar coincidence are Christmas Day and Independence Day, falling on two consecutive dates.
In German, a bridge-related term is also used: a day taken off from work to fill the gap between a holiday Thursday (or Tuesday) and the weekend is called a Brückentag ("bridge day") in Germany and Switzerland, and a Fenstertag ("window day") in Austria. Since Ascension day is a holiday throughout Germany and Corpus Christi is a holiday in large parts of the country (both of these holidays are always on Thursdays), such "bridge days" are fairly common, though always inofficial in character. The "bridge day" terminology is also used in Israel ("yom gishur"/"יום גישור") and The Netherlands ("brugdag").
The term długi weekend (Polish for long weekend) is also commonly used in the Polish language. In Poland, such a phenomenon usually occurs several times a year. As well as the Easter weekend and the Christmas weekend, there is Corpus Christi weekend (Corpus Christi is always on Thursday and people usually take Friday off as well) and it may occur also around other holidays. However, the best known long weekend is at the beginning of May, when there are holidays of Labour Day on May 1 and 3rd May Constitution Day. The weekend can in fact be up to 9 days long (April 28 – May 6) and, taking one to three days off work, Poles often go for small holidays then.
In Norwegian, the term "oval weekend" is used. An ordinary weekend is conceived of as "round" (although this is not stated explicitly), and adding extra days off makes it "oval". Norwegians also refer to "inneklemte" [squashed in]days, which are between a public holiday and a weekend. This is typical for the Friday after Ascension Day, which always falls on a Thursday. It is common to work in such days so as to be able to take them off and extend the weekend to four days.
Also in Swedish, the days between a weekend and a holiday are called "klämdagar" (squashed in days).
In Argentina, some national holidays that occur on a Tuesday, Wednesday, Thursday or Friday (sometimes even on a Saturday) are officially moved to the closest Monday in order to create a long weekend.
In Brazil, when a holiday occurs in a Tuesday or a Thursday, some sectors of the society, as government and education, turn the day between the holiday and the weekend into a holiday. The four-day or even the three-day weekends are called feriados prolongados ("Extended holidays") or its popular form feriadão ("big holiday"). The bridge day is usually called "imprensado" ("pressed (in between)").
In Indonesia, when a holiday occurs on a Tuesday and Thursday, the day between that day and the weekend is informally termed 'Hari Kejepit Nasional' (lit. National Squeezed Day) causing some institutions to declare a day-off or even to some students or employees to declare themselves a day-off creating a very long weekend.