/ ˈstændbaɪ; NAmE / noun , adjective
■ noun
( pl. stand·bys ) noun
a person or thing that can always be used if needed, for example if sb/sth else is not available or if there is an emergency :
I always keep a pizza in the freezer as a standby.
a standby electricity generator
•
IDIOMS
- on standby
■ adjective
[ only before noun ] a standby ticket for a flight, concert, etc. cannot be bought in advance and is only available a very short time before the plane leaves or the performance starts