The bond between brothers-in-arms on the battlefield is most precious.
Tips
history
From the Book of Songs (诗经·秦风·无衣): 与子同袍 (yǔ zǐ tóng páo) 'wearing the same robe with you' — soldiers shared robes (袍) and inner garments (泽), so 袍泽 became a poetic term for fellow soldiers.
register
Literary and formal — used in writing, eulogies, and military contexts. Modern speech prefers 战友 (zhànyǒu).
