1The brain — the main organ of the central nervous system, housed in the skull and responsible for thought, perception, and movement. Used broadly in medical and scientific contexts.
脳卒中は脳への血流が滞ることで起こる病気だ。
A stroke is a condition caused by disrupted blood flow to the brain.
MRI検査で脳の画像を撮影した。
They took images of my brain with an MRI scan.
睡眠は脳の疲労回復にとって欠かせない。
Sleep is essential for the brain to recover from fatigue.
近年、脳科学の研究が急速に進んでいる。
In recent years, research in brain science has been advancing rapidly.
人間の脳は全身のエネルギーの約20%を消費する。
The human brain consumes about 20 percent of the body's energy.
2By extension, thinking ability or mental capacity — one's 'brain' in the sense of intellect. Used in expressions like 脳を使う ('use your brain') or 脳をフル回転させる ('work at full mental capacity').
この問題を解くには脳をフル回転させる必要がある。
You need to use your brain at full throttle to solve this problem.
最近あまり脳を使っていない気がする。
I feel like I haven't been using my brain much lately.
パズルを解くのは脳のトレーニングになる。
Solving puzzles is good training for the brain.