This is the 2263rd most frequent German word.
gehirn
Brain.
Here, 'Gehirn' is used as a noun to refer to the organ that controls thoughts, memory, emotions, and physical functions in humans.
Das Gehirn ist das wichtigste Organ des menschlichen Körpers.
The brain is the most important organ of the human body.
In this sentence, 'Gehirn' metaphorically represents the intellectual or cognitive functions of the individual.
Sein Gehirn arbeitete auf Hochtouren, um das Problem zu lösen.
His brain was working at full speed to solve the problem.
Here, 'Gehirn' is used figuratively in plural form to signify the intellectual driving force or creative mind behind an endeavor.