subject matter
US /ˈsʌbdʒekt ˌmætər/
UK /ˈsʌbdʒekt ˌmætər/

1.
assunto, matéria
the topic or theme of a book, discussion, or work of art
:
•
The subject matter of the painting was a landscape.
O assunto da pintura era uma paisagem.
•
The professor's lecture covered a wide range of subject matter.
A palestra do professor cobriu uma ampla gama de assuntos.