time set usually one hour ahead of the local standard time, widely adopted in the summer to provide extra daylight in the evening 
WordReference Random House Learner's Dictionary of American English © 2025
ˈday•light-ˈsav•ing (or ˈday•light ˈsav•ing) ˌtime, n. [uncountable]
WordReference Random House Unabridged Dictionary of American English © 2025- Timetime in which clocks are set one hour ahead of standard time.
 
day′light-sav′ing time′ 
(dā′līt′sā′ving),USA pronunciation 
- Timethe civil time observed when daylight saving is adopted in a country or community. Also, day′light-sav′ings time′.
 
- 1905–10
 
Collins Concise English Dictionary © HarperCollins Publishers::
'daylight saving time' also found in these entries (note: many are not synonyms or translations):
British Summer Time
 - DST
 - EDT
 - daylight-saving time
 - fast
 - fast time
 - split-time
 - summer time