重点(zhòng diǎn) - key point, focus, emphasis, main in Mandarin

重点 (zhòng diǎn) is the point that matters most: the key part of a lesson, the focus of a project, the thing you would say if you only had one sentence. 划重点 (huà zhòng diǎn) is to underline the important bits, and it has become slang for spelling out the takeaway.

It also works in front of a noun as a modifier meaning key or flagship: 重点大学 (zhòng diǎn dà xué) is a top-tier university, 重点项目 (zhòng diǎn xiàng mù) a priority project. No 的 (de) is needed in that position.

Keep it apart from 重要 (zhòng yào), which is the adjective important. A thing is 很重要 (hěn zhòng yào), but it is 一个重点 (yī gè zhòng diǎn). Saying 很重点 (hěn zhòng diǎn) is the mistake to avoid.