Fallback/ˈfɔːlbæk/ Definition 1 of 3Pro Tip 1/3Plan B Fallback can imply a secondary plan, often less ideal but reliable. If our fundraiser fails, selling T-shirts will be our fallback. Pro Tip 2/3Not Primary A fallback isn't your first choice; it's what you resort to when needed. I applied for several jobs, using retail work as a fallback. Pro Tip 3/3Security Sense Fallback evokes a sense of security, as an alternative is ready. In case of rain, the fallback will be to have the event indoors.