A topic refers to the general subject or subject matter of a text, conversation, or piece of writing. It is usually a broad term or a general area of discussion.
On the other hand, a central/main idea refers to the specific point or statement that the author or speaker is making about the topic. It represents the main focus or purpose of the text and encapsulates the main point the author wants to convey to the audience.
To illustrate with an example, suppose the topic is "climate change." The main idea could be "human activities are causing significant and detrimental effects on the Earth's climate." In this case, the topic is the broad subject of climate change, while the central/main idea is the specific viewpoint or statement being made about climate change.
What's the difference between a topic and a central/main idea?
1 answer