Adverb
moving from one place to another and back again
Source: WordNetLife swings like a pendulum backward and forward between pain and boredom. Arthur Schopenhauer
I loved you backward and forward in time. I loved you beyond boundaries of time and space. Dan Simmons
he traveled back and forth between Los Angeles and New York Source: Internet
the treetops whipped to and fro in a frightening manner Source: Internet
the old man just sat on the porch and rocked back and forth all day Source: Internet
For backward and forward compatibility LFNs were implemented as an optional extension on top of the existing FAT file system structures using a workaround in the way directory entries are laid out. Source: Internet