Definition of "stand-by" [stand•-by]

• A preparatory order, equivalent to Be ready. (verb-intransitive)
• One who, or that which, stands by one in need; something upon which one relies for constant use or in an emergency. (noun)

Gnu Collaboartive International Dictionary of English: licensed under The Code Project Open License (CPOL)

• "There is simply not enough room in a normal home for all this gear to be on ready stand-by to go."
• "Australia have put Usman Khawaja on stand-by in case Michael Clarke fails to recover from injury for the first Ashes Test"
• "Instead, most companies either kept their rigs on stand-by or kept them busy with jobs that weren't covered by the moratorium, such as cleaning up old wells."