The bora is a northerly to north-easterly katabatic wind in areas near the Adriatic Sea. Similar nomenclature is used for north-eastern winds in other littoral areas of eastern Mediterranean and Black Sea basins.

It is known in Greek as μπόρα (mpóra, pronounced bora) and Italian as bora. In English, the name bora is used. The Serbo-Croatian name bura and Slovene burja are not etymologically related to bora; they derive from Common Slavic burja 'storm' (from the verb *burĭti), and the meaning 'bora' developed later.

The same root as bora is found in the name of the Greek mythological figure of Boreas (Βορέας), and the Modern Greek word for the north wind βοράς. Historical linguists speculate that the name may derive from a Proto-Indo-European root *g^worh_x- 'mountain', which gave rise to Slavic gora and Sanskrit giri-, both 'mountain'.

The changeable bora can often be felt all over Adriatic Croatia, the Montenegrin Littoral, the Slovenian Littoral, Trieste, and the rest of the Adriatic east coast. It blows in gusts. The bora is most common during the winter. It affects coastal areas and it weakens into the open sea.

It blows hardest when a polar high-pressure area sits over the snow-covered mountains of the interior plateau behind the Dinaric coastal mountain range and a calm low-pressure area lies further south over the warmer Adriatic. As the air grows even colder and thus denser at night, the bora increases. Its initial temperature is so low that even with the warming occasioned by its descent it reaches the lowlands as a cold wind.

The wind takes two different traditional names in areas of Italy and Croatia depending on associated meteorological conditions: the "light bora" (Italian: bora chiara) is a bora in the presence of anticyclone clear skies, whereas cyclone clouds gathering on the hilltops and moving towards the seaside with rain or snow characterize the "dark bora" (Italian: bora scura, Croatian: škura bura).

The area where some of the strongest bora winds occur is the Velebit mountain range in Croatia. This seaside mountain chain, spanning 145 km, represents a huge weather and climatic divide between the sharp continental climate of the interior, characterized by significant day/night temperature differences throughout the year, and the Adriatic coast, with a Mediterranean climate. The bora occurs because these two divided weather systems meet and tend to equalize over the mountain range.

Sailing during the bora can be challenging and it requires caution, regarding readiness of both the boat and its crew. Short, high waves with white crests are its characteristics, making the navigation difficult. The small drops formed by the wind create a so-called "sea smoke" that reduces the visibility significantly. Experienced seamen have a proverb: "When the bora sails, you don't!" Sailing can be extremely dangerous for an inexperienced navigator in the Velebit Channel because the wind can start suddenly on a clear and calm day and result in major problems, frequently also affecting road traffic.