一个主意用英语怎么说

"An idea" in English can be referred to as "a concept," "a notion," or "a proposal." The source of the phrase "an idea" comes from the Latin word "idea," which means "a form, shape, or appearance."

Examples:

I have an idea for a new business venture.
She came up with an idea to solve the problem.
The new design is based on the idea of simplicity.

Translations:

我有一个新商业项目的想法。
她想出了一个解决问题的想法。
这个新设计是基于简单的理念。