Meaning of back up

Definition of back up

(verb) give moral or psychological support, aid, or courage to; "She supported him during the illness"; "Her children always backed her up"
move backwards from a certain position; "The bully had to back down"
establish as valid or genuine; "Can you back up your claims?"
make a copy of (a computer file) especially for storage in another place as a security copy; "You'd better back up these files!"
become or cause to become obstructed; "The leaves clog our drains in the Fall"; "The water pipe is backed up"

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