1. Borders or boundaries that are not clearly defined, established, or agreed upon; ambiguous or unclear demarcation lines between territories or concepts
The treaty left fronteiras indeterminadas between the two nations, leading to future disputes.
O tratado deixou fronteiras indeterminadas entre as duas nações, levando a futuros conflitos.
2. In abstract contexts: conceptual or figurative boundaries that lack clear definition or delimitation
The fronteiras indeterminadas between art and science continue to fascinate researchers.
As fronteiras indeterminadas entre arte e ciência continuam a fascinar pesquisadores.