subject matter
noun [uncountable]the ideas or information contained in a book, speech, painting, etc. （著作、讲话、绘画等的）主题，题材，主要内容 The artist was revolutionary in both subject matter and technique. 这位画家在内容和手法两方面都有重大创新。 She's searching for subject matter for her new book. 她要写一部新书，正寻找题材。