back up

an accumulation caused by clogging or a stoppage;
someone who takes the place of another (as when things get dangerous or difficult);
a musical part (vocal or instrumental) that supports or provides background for other musical parts
(computer science) a copy of a file or directory on a separate storage device;
the act of providing approval and support;
give moral or psychological support, aid, or courage to;
move backwards from a certain position;
establish as valid or genuine;

make a copy of (a computer file) especially for storage in another place as a security copy;