well in serbian its: 'Osmina finala' which is basically 1/16 finals.
I probably don't know how it goes in english, if you start counting backwards: finals > semi-finals(1/4finals) > quarter finals(1/4 finals).... and then? 1/16 finals = ?
Maybe the word I'm missing was my initial question instead of giving an example like 'Round of 64'.
At least its good to know, with the question like this, I'm definitely at the right place