A set phrase referring to the fundamental duality of existence; often used in philosophical, literary, or dramatic contexts.
彼は生と死の境をさまよった。
He wandered the border between life and death.
この小説は生と死をテーマにしている。
This novel deals with the theme of life and death.
Compound of 生 (せい, 'life') + と (conjunctive particle) + 死 (し, 'death'). A straightforward Sino-Japanese phrase.