Otsukaresamadeshita is a greeting in Japanese which people tell others when the other person has just finished a work or is going home from a long days of work, or maybe after a speech he/she has given, or after a stage performance etc. It is a nuance word, meaning that it does not have any specific meaning but has several definitions and applications depending on situations. I think it will be a little bit easier if you break down the word (even though it does not mean much,it will give you a good sense of the word!) "O" at the beginning is used when talking in a respective manner toward someone else (like "Oshigoto wa nandesuka"=> What is your occupation?). "Tsukare" comes from "Tsukareru" which means "to get tired". "Sama" is a suffix used after addressing someone and makes the addressed person very respective. "Deshita" is the past of "Desu". (***I am assuming you already know most of the words!) So, adding up all the words together gives a meaning like this "Oh! You have worked a lot today and have become tired. Thanks for your hard work!" And yes, you can use "お疲れ様でした" while writing; it is the Kanji of the word "おつかれさまでした" and has the same pronunciation. If you still want to know more, then I think this page has some nice explanations for you. Other than that, you can also search the Google easily since many many websites have already explained about this word also!!! http://japanesepro.blogspot.com/2011/03/what-does-otsukaresama-desu-really-mean.html Hope my answer helped! ^_^