Donaudampfschiffahrtselektrizitätenhauptbetriebswerkbauunterbeamtengesellschaft
Donaudampfschiffahrtselektrizitätenhauptbetriebswerkbauunterbeamtengesellschaft is a compound word that serves as an example of the virtually unlimited compounding of nouns that is possible in many Germanic languages. According to the 1996 "Guinness Book of World Records", it is the longest word published in the German language.
Euouae
According to the "Guinness Book of World Records", at six letters long, "Euouae" is the longest word in the English language made up of nothing but vowels (the v spelling notwithstanding), and also the English word with the most consecutive vowels. As a mnemonic coming from Latin, it is unclear that it should count as an English word; however, it is found in the unabridged Collins English Dictionary.