1. the reverse or opposite aspect of something
on the flip side, something good/bad might happen
The 'flip side' of something is the reverse or opposite aspect of something. You might use the expression 'the flip side of the argument' for example to talk about things from the opposite side or perspective as your own. Something considered 'the flip side' may also have the connotation of being less popular. This expression comes from the days of vinyl records when the popular music or release was placed on one side of the record and a contrasting song was usually placed on the other side. If you say 'see you on the flip side' it means you hope to see someone after an event has occurred. This is a casual expression used more in social and informal contexts.