Example: "A standby generator"
To wait in expectation of some event; to make ready.
Example: "Please stand by for more instructions."
To remain loyal or faithful to.
Example: "Even though money is scarce sometimes, ann stands by her decision to be a full-time mother."
To support; to continue to support despite things being bad.
Example: "They stood by us all along and it's awesome to see them out here to support us today."
To do nothing. to be inactive in a situation.
Example: "I can't simply stand by and watch you ruin your life."
To be ready to provide assistance if required.
Example: "The tug stood by in case it was needed."