All them are common ways to say "bye" in Portuguese. - ATÉ LOGO It's used to express the idea of "see you soon" in all lusophone regions. Other similar expressions are: ATÉ BREVE, ATÉ JÁ (see you soon) and ATÉ A VISTA, ATÉ MAIS (see you later). - ADEUS It's used to say goodbye in a way you wish "blessings" (like the word "goodbye" in English that is a contract of "God be with you"). ADEUS sometimes is polemic because in some regions of Brazil, people see the ADEUS like a word that express the idea that you will not see the person for a long time. But in majority of lusophone regions ADEUS just mean a way to say "goodbye". Other similar expressions are: VÁ COM DEUS (leave with God), PASSE BEM (farewell). - TCHAU (or XAU) It's the Portuguese version of the popular Italian word "ciao". It's an almost universal expression that you can use everytime you want to say "bye". P.S.: Another ways to express goodbye/bye/farewell in Portuguese: ATÉ AMANHÃ (see you later tomorrow), ATÉ A PRÓXIMA (see you the next time), BOA NOITE (good night)

'Adeus' is when you will no longer see the person again or you don't want see it anymore. 'Tchau' and 'até logo' is when you will see the person soon, something like 'see you later' and are the same thing, but tchau is more informal than até logo.

Relativamente a tchau, essa expressão não existe em Português. Relativamente a adeus e até logo, a primeira trata-se de uma despedida mais prolongada e a segunda uma despedida mais breve (no mesmo dia) On respect to tchau, this expression does not exist in Portuguese. Relatively to adeus e até logo , the first one it is for a longer period of time and the second for a shorter period of time (inside the same day)

Hi! There is some differences in the use of them. But all of them meant to say goodbye. "Adeus" its used when you mean to say goodbye for a longer period of time, sometimes used to say goodbye forever. "Tchau" and "até logo" are used like goodbye.