Bedtime is the hour when you are supposed to go to sleep. Half past eight, teeth brushed, one more story.
It belongs to childhood more than to adults, and it brings a small vocabulary with it: a bedtime story, a bedtime routine, a bedtime drink. Adults use it about themselves half-jokingly — it's past my bedtime, said while standing up to leave a party. It works as an adjective in front of a noun, as in bedtime reading. And it gives you the standard phrase for a very late night.
1nounbedtimeThe time at which you normally go to bed.
“The children have a strict bedtime.”
Middle English
bedtyme
English, today
bedtime
From Middle English bedtyme, bed-tyme, bedetyme, bedde tyme, equivalent to bed + time. Compare earlier Old English bedtīd (“bedtime”). Compare also West Frisian bêdtiid (“bedtime”), Dutch bedtijd (“bedtime”), stq Bädegungenstied (“bedtime”) literally “bed-goings-time”, German Low German Beddgahnstied, Bettgahnstiet (“bedtime”) literally “bed-goings-time”.
Etymology from Wiktionary, CC BY-SA