(computer science) a copy of a file or directory on a separate storage device; "he made a backup in case the original was accidentally damaged or erased"
an accumulation caused by clogging or a stoppage; "a traffic backup on the main street"; "he discovered a backup in the toilet"
drawing a comparison in order to show a similarity in some respect; "the operation of a computer presents and interesting analogy to the working of the brain"; "the models show by analogy how matter is built up"
an inference that if things agree in some respects they probably agree in others