‘次数’ (cì shù) is a noun meaning ‘number of times’—it quantifies how often an action, event, or occurrence happens. The first character 次 (cì) means ‘time’ or ‘occasion’, and the second character 数 (shù) means ‘number’ or ‘count’. Together, they form a compound noun that functions as a measure word phrase, always used after a numeral or quantifier (e.g., 三次, 无数次) or with verbs like ‘增加’ (increase), ‘减少’ (decrease), or ‘计算’ (calculate). It’s neutral in register and appears frequently in daily speech, instructions, statistics, and health contexts (e.g., medication dosage, exercise repetition).

Unlike standalone measure words like ‘次’ alone—which can mean ‘a time/instance’—‘次数’ specifically emphasizes the *countable quantity* of repetitions. It cannot stand alone without a number or modifier (you wouldn’t say ‘我做了次数’; instead, you’d say ‘我做了三次’ or ‘这个动作的次数’). It’s commonly paired with verbs like ‘达到’ (reach), ‘超过’ (exceed), or ‘控制在…以内’ (keep within…).