高速 (gāo sù) literally means 'high speed' — 高 (gāo) means 'high' or 'tall', and 速 (sù) means 'speed' or 'velocity'. Together, they form a compound adjective describing things that operate, move, or function at high speed. It is most commonly used in technical, transportation, and infrastructure contexts.

This term frequently appears in compound nouns like 高速公路 (gāosù gōnglù, 'expressway' or 'freeway'), 高速列车 (gāosù lièchē, 'high-speed train'), and 高速网络 (gāosù wǎngluò, 'high-speed internet'). While it can modify nouns directly as an adjective (e.g., 高速发展), it rarely stands alone as a noun in everyday speech. Its usage implies efficiency, modernity, and advanced capability — often associated with China’s rapid infrastructure development and technological upgrades.