stand·by
(stănd′bī′)n. pl. stand·bys 1. One that can always be relied on, as in an emergency.
2. One kept in readiness to serve as a substitute.
3. A mode of operation for a computer, television, or other electronic device in which the power is on and the device is ready for immediate use.
adj.1. Kept in reserve for use when needed: a standby generator.
2. Of, relating to, or waiting for unreserved travel space that is made available by an airline only shortly before departure: standby passengers.
adv. On a standby basis: flew standby to New York.
Idiom: on standby1. Ready and available.
2. As a standby passenger.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
stand•by
(ˈstændˌbaɪ)
n., pl. -bys,
adj., adv. n. 1. a staunch supporter or adherent.
2. something upon which one can rely, as for regular use.
3. something or someone held ready to serve as a substitute, as in an emergency.
4. a traveler assured of transportation, as on a plane, only when another passenger cancels.
adj. 5. kept ready for use as a substitute: a standby player.
6. of, for, or traveling as a standby: a standby flight.
adv. 7. as a standby: to fly standby to Rome.
Idioms: on standby, ready to act immediately when called upon.
[1790–1800]
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.