大脑用英语可以说作"brain"。来源方面，brain 这个词来自古英语的"brægn"，最初的意思是"脑袋"或"智慧"。例如：

The brain is the most complex organ in the human body. (大脑是人体中最复杂的器官。)

She had a headache because she was using her brain too much. (她头疼是因为她用脑太多了。)

He was born with a brain defect. (他生来就有大脑缺陷。)