raindate means an alternative date on which an event will be held if it rains on the originally scheduled date. Lexicurio rates it Sui generis — a strength score of 89 out of 100.
Etymology
From rain + date.
noun
- An alternative date on which an event will be held if it rains on the originally scheduled date.“It's Gay Pride Day, happening this year on Saturday, June 15th (Raindate: Sunday, June 16)”