1. noun /ˈɛ.ɹə(ɹ)/
a) A mistake; an accidental wrong action or a false statement not made deliberately.
b) A failure to complete a task, usually involving a premature termination.
Syn: blooper, blunder, boo-boo, defect, fault, faux pas, fluff, gaffe, lapse, mistake, slip, stumble, thinko
2. verb /ˈɛ.ɹə(ɹ)/
a) To function improperly due to an error, especially accompanied by error message.
The web-page took a long time to load and errored out.
b) To show or contain an error or fault.
Remove that line of code and the script should stop erroring there.
Wikipedia foundation.