The phrase "main point" refers to the most salient or crucial aspect of a piece of information or argument. Other words that can be used to convey the same idea include "key point," "central idea," "core concept," and "primary focus." Each of these synonyms emphasizes the main idea or thesis of a message or text, highlighting its most important or significant aspect. Whether used in academic writing, business communication, or casual conversation, these terms offer a way to communicate the essential content of a topic while also adding clarity and precision to one's language.