summer timeBrE /ˈsʌmə taɪm/ 🔊NAmE /ˈsʌmər taɪm/ 🔊 (BrE) (NAmE ˈdaylight saving time) noun [uncountable] the period during which in some countries the clocks are put forward one hour, so that it is light for an extra hour in the evening 夏令时（有些国家实行夏时制，将时钟拨快一小时，以节约照明能源）