Estonian
Estonian has many long words; one of the more notable ones, at 24 characters, is kuulilennuteetunneliluuk, meaning "the hatch a bullet flies out of when exiting a tunnel". It is notable as it is also a palindrome, meaning it can be read from both ends.
One other long word is uusaastaöövastuvõtuhommikuidüll at 31 characters, denoting an ideallistic morning after the new year. It can be used in a sentence such as Maalilist jõuluööeelootusaega ja illuminaarses aoõhetuses uusaastaöövastuvõtuhommikuidülli to say "merry Christmas and a happy new year".
Another good example of a long word is "sünnipäevanädalalõpupeopärastlõunaväsimus" which means “The tiredness one feels on the afternoon of the weekend birthday party”. Or if you break it down into parts “birth.day.week.end.party.after.lunch.tiredness”.
Read more about this topic: Longest Words