In 1154, a town called قلون (Qlwn or Qalaven, possibly derivations of Kalevan or Kolyvan) was put on the world map of the Almoravid by the Arab cartographer Muhammad al-Idrisi, who described it as "a small town like a large castle" among the towns of 'Astlanda'. It was suggested that Quwri may have denoted a predecessor of the modern city. Another possibly one of the earliest name of Tallinn is Kolyvan (Russian: Колывань), which has been discovered from East Slavic chronicles and may somehow be connected to the Estonian mythical hero Kalev. However, a number of modern historians have considered connecting al-Idrisi placename(s) with Tallinn unfounded and erroneous.
Henry of Livonia in his chronicle called the town with the name that is also known to have been used up to the 13th century by Scandinavians: Lindanisa (or Lyndanisse in Danish, Lindanäs in Swedish and Ledenets in Old East Slavic). It has been suggested that the archaic Estonian word linda is similar to the Votic word lidna 'castle, town'. According to this suggestion, nisa would have the same meaning as niemi 'peninsula', producing Kesoniemi, the old Finnish name for the city.
Another ancient historical name for Tallinn is Rääveli in Finnish. The Icelandic Njal's saga mentions Tallinn and calls it Rafala, which is probably based on the primitive form of Revala. This name originated from Latin Revelia (Revala or Rävala in Estonian), the adjacent ancient name of the surrounding area. After the Danish conquest in 1219, the town became known in the German, Swedish and Danish languages as Reval (Latin: Revalia). Reval was in official use in Estonia until 1918.
The lesser coat of arms of Tallinn, which depicts the Dannebrog
The name Tallinn(a) is Estonian. It is usually thought to be derived from Taani-linn(a), (meaning 'Danish-town) (Latin: Castrum Danorum), after the Danes built the castle in place of the Estonian stronghold at Lindanisse. However, it could also have come from tali-linna ('winter-castle or town'), or talu-linna ('house/farmstead-castle or town'). The element -linna, like Germanic -burg and Slavic -grad / -gorod, originally meant 'fortress', but is used as a suffix in the formation of town names.
The previously-used official names in German Reval (help·info) and Russian Revel (Ревель) were replaced after Estonia became independent in 1918.
At first, both forms Tallinna and Tallinn were used. The United States Board on Geographic Names adopted the form Tallinn between June 1923 and June 1927. Tallinna in Estonian denotes the genitive case of the name, as in Tallinna Reisisadam ('the Port of Tallinn').
In Russian, the spelling of the name was changed from Таллинн to Таллин (Tallin) by the Soviet authorities in the 1950s, and this spelling is still officially sanctioned by the Russian government, while Estonian authorities have been using the spelling Таллинн in Russian-language publications since the restoration of independence. The form Таллин is also used in several other languages in some of the countries that emerged from the former Soviet Union. Due to the Russian spelling, the form Tallin is sometimes found in international publications; it is also the official form in Spanish.
Other variations of modern spellings include Tallinna in Finnish, Tallina in Latvian and Talinas in Lithuanian.