Compound (linguistics)
Agglutinative languages tend to create very long words with derivational morphemes. Compounds may or may not require the use of derivational morphemes also.
The longest compounds in the world may be found in the Finnic and Germanic languages. In German, extremely 
extendable compound words can be found in the language of chemical compounds, where, in the cases of biochemistry and polymers, they can be practically unlimited in length, mostly because the German rule suggests combining all noun adjuncts with the noun as the very last stem. German examples include (color television set), (radio remote control), and the often quoted jocular word (originally only two Fs, Danube steamboat shipping company captain['s] hat), which can of course be made even longer and even more absurd, e.g. "Donaudampfschifffahrtsgesellschaftskapitänsmützenreinigungsausschreibungsverordnungsdiskussionsanfang" ("beginning of the discussion of a regulation on tendering of Danube steamboat shipping company captain hats") etc. According to several editions of the Guinness Book of World Records, the longest published German has 79 letters and is " Donaudampfschiffahrtselektrizitätenhauptbetriebswerkbauunterbeamtengesellschaft "("Association for Subordinate Officials of the Main Electric[ity] Maintenance Building of the Danube Steam Shipping"), but there is no evidence that this association ever actually existed. The word is so absurd that it was obviously invented as a joke, which is emphasized by the illogical use of the plural of "electricity".
Österreichisches Wörterbuch
The Österreichisches Wörterbuch (English: Austrian Dictionary), abbreviated ÖWB, is the official dictionary of the German language in the Republic of Austria. It is edited by a group of linguists under the authority of the Austrian Federal Ministry of Education, Arts and Culture ("Bundesministerium für Unterricht, Kunst und Kultur"). It is the Austrian counterpart to the German "Duden" and contains a number of terms unique to Austrian German or that are more frequently used or differently pronounced there. A considerable amount of this "Austrian" vocabulary is also common in Southern Germany, especially Bavaria, and some of it is used in Switzerland as well. The most recent edition is the 43rd from 2017. Since the 39th edition from 2001 the orthography of the "ÖWB" was adjusted to the German spelling reform of 1996. This dictionary is also in official use in the Italian province of South Tyrol.