The word “die Semmel (-n)” is not a purely Austrian word. More like a synonym for “das Brötchen(-s)” in literary German. The difference is that the Austrians call the word “das Brötchen” what is called in standard German “belegtes Brot” – “bread on which something is put” (what we call a sandwich or canapé).
Recently, the assortment has changed very much in the direction of small products with different recipes. Here in standard German all these things, as before, are called buns – “das Brötchen”. And in the Austrian German classic buns remain “die Semmel (-n)”, and all these new kinds of buns with stuffings began to be called “der Weckerl”.
For example, what the German calls “Mohnbrötchen” – “poppy bun” – the Austrian will call “Mohnwecker”.
Let’s do it again for the fixation:
- belegtes Brot (Hochdeutsch) – das Brötchen(-s) (österreiches Deutsch) – sandwich/canape;
- die Semmel/das Brötchen (Hochdeutsch) – die Semmel (österreiches Deutsch) – bun;
- das Brötchen (Hochdeutsch) – der Weckerl (österreiches Deutsch) – buns filled with buns;