海峡 (hǎi xiá) literally combines 海 (hǎi), meaning 'sea' or 'ocean', and 峡 (xiá), meaning 'gorge' or 'narrow passage'. Together, they form the precise geographical term for a narrow body of water connecting two larger bodies of water — what English calls a 'strait'. This word is used exclusively for natural marine passages, not man-made canals. It appears frequently in geography, navigation, politics, and news reports about maritime boundaries or regional tensions.

Unlike general terms for 'waterway' or 'channel', 海峡 emphasizes both the narrowness and the connection between seas. Famous examples include the Taiwan Strait (台湾海峡), the Strait of Malacca (马六甲海峡), and the Bering Strait (白令海峡). The term carries formal, technical, and sometimes geopolitical weight — it’s rarely used in casual speech unless referring to well-known straits.