The word vanilla has a few meanings:

1. A flavor that comes from the seed pods of tropical orchid plants. Vanilla flavoring appears in ice cream, cookies, cakes, and countless other desserts. Real vanilla comes from long, dark pods that grow on vines in warm places like Madagascar and Mexico. Inside these pods are thousands of tiny seeds that contain the flavor. The process of growing, harvesting, and preparing vanilla is so labor-intensive that real vanilla extract can cost more than many other flavorings.
2. Something plain, ordinary, or without special features. When someone calls something vanilla, they mean it's the basic version without extras or excitement. A vanilla video game might be the original version before any expansion packs or modifications. A vanilla approach to solving a problem means using the most straightforward, standard method. This meaning comes from vanilla ice cream being considered the most basic flavor, even though real vanilla actually has a complex, subtle taste that many people love.

People sometimes use plain vanilla to emphasize that something is especially simple or unadorned, like a plain vanilla checklist with no fancy formatting.