noun
central idea; main thought
Refers to the core concept or guiding principle of a text, argument, or philosophy.
この論文の中心思想は何ですか。
What is the central idea of this paper?
主題 is a broader 'theme' or 'subject', while 中心思想 specifically means the central idea or core thought.
Compound of 中心 (center) and 思想 (thought, ideology).