时代 (shí dài) means 'era' or 'age'—a long, historically significant period defined by distinctive social, cultural, technological, or political characteristics. The first character 时 (shí) means 'time' or 'moment', and the second character 代 (dài) means 'generation' or 'dynasty'; together, they convey a broad span of time marked by shared conditions across generations.

This word is commonly used in academic, historical, journalistic, and formal contexts—for example, when discussing the Industrial Era (工业时代), the Digital Age (数字时代), or China’s Reform Era (改革开放时代). It carries a sense of scale and significance: it’s not just any period, but one with defining features that distinguish it from others before and after. While often paired with modifiers (e.g., 新时代 xīn shídài 'the New Era'), it can stand alone as a noun subject or object in sentences about history, progress, or societal change.