plan B
A secondary plan to be undertaken in case the original plan ("plan A") fails or cannot be implemented; a backup plan. We're running a bit late, so how about plan B—instead of getting dinner before the movie, let's just get some popcorn at the theater and eat something proper afterward. Well, the diagnostics test didn't reveal any issues with the server. Do you have a plan B?
plan B
COMMON Someone's plan B is a second plan they have that they will use if their first plan is not successful. It was too late to rethink my plan, and due to the fact that I didn't have a plan B, I was stuck with it.
plan B
an alternative strategy. 1999 8 Days And if that doesn't work, well, there's always Plan B.