1. A subject matter that is clearly specified, fixed, or determined; a topic with clear boundaries and specific scope
The teacher assigned a definite topic for the research paper: the history of renewable energy.
A professora atribuiu um tópico definido para o trabalho de pesquisa: a história das energias renováveis.
2. In linguistics, a noun phrase that refers to a specific, known entity
In the sentence 'The cat sat on the mat,' 'the cat' is a definite topic.
Na frase 'O gato sentou-se no tapete', 'o gato' é um tópico definido.