overnight

from The American Heritage® Dictionary of the English Language, 5th Edition.

• adjective Lasting for, extending over, or remaining during a night.
• adjective For use over a single night or for a short journey.
• adjective Mailed for guaranteed delivery on the next day.
• adjective Happening as if in a single night; sudden.
• adverb During or for the length of the night.
• adverb In or as if in the course of one night; suddenly.
• noun An overnight stay or trip.
• intransitive verb To spend the night.
• intransitive verb To send by mail or other courier for delivery the next day.

from The Century Dictionary.

• Done or occurring overnight; specifically, in racing, noting an entry made just before the day of the race, or a race arranged ‘overnight.’
• noun In racing, a race (or entry) arranged the night before it is run.
• Through the night; during the evening or night; especially, during the night just passed.
• noun Night before bedtime, referring to the night just passed.

from the GNU version of the Collaborative International Dictionary of English.

• adverb In the fore part of the night last past; in the evening before.
• adverb Throughout the night.
• adverb During the night; hence, in a short period of time.
• adjective Ocurring or accomplished during one night.
• noun rare The fore part of the night last past; the previous evening.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adverb Throughout the night
• adverb During a single night
• adverb In a very short (but unspecified) amount of time
• adjective Occurring between dusk and dawn.
• adjective Complete before the next morning.
• noun Items delivered or completed overnight.
• noun An overnight stay, especially in a hotel or other lodging facility.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• adverb during or for the length of one night
• adverb happening in a short time or with great speed
• adjective lasting, open, or operating through the whole night