Overnight is defined as something that extends from evening until morning, or something that happens very quickly.(adverb)
Overnight means to ship something to be delivered the next day, or to stay somewhere for the evening and not leave until morning.(verb)
The definition of an overnight is a stop that lasts for one evening.(noun)
If you spend one night in New York City, this is an example of an overnight.
See overnight in Webster's New World College Dictionary
See overnight in American Heritage Dictionary 4
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