Information or matters that should be kept unknown to others; something confidential or private.
それは会社の重要な秘密なので口外しないでください。
That's an important company secret, so please don't disclose it.
友達の秘密を守るのは信頼関係にとって大切だ。
Keeping a friend's secret is important for trust.
個人情報は秘密に扱う必要がある。
Personal information needs to be treated confidentially.
A mystery or something unexplained; a puzzling or enigmatic matter.
宇宙の秘密を解き明かす研究が進んでいる。
Research to uncover the mysteries of the universe is progressing.
彼女の成功の背景には多くの秘密があるらしい。
It seems there are many mysteries behind her success.
A secret (tip or key) to success or a technique—e.g., 'the secret of success.'
彼の成功の秘密は毎日の努力だと語った。
He said the secret to his success was daily effort.
料理の秘密は良い素材の選び方にある。
The secret of cooking lies in choosing good ingredients.
Esoteric or secret teachings in Buddhism—special doctrines passed on within certain sects.
密教におけるいくつかの儀礼は外部には秘とされている。
Some rituals in esoteric Buddhism are kept secret from outsiders.