Plantains are closely related to which popular household fruit?

A plantain to the untrained eye could easily be mistaken for a banana. In fact, it belongs to Musaceae, the banana family of plants, and it's closely related to the common banana. Believed to be native to Southeast Asia, plantains are grown in tropical regions around the world and in a variety of cuisines. Unripe plantains are green to yellow, difficult to peel, and the fruit is hard with a starchy flavor—this is the perfect stage for boiling and frying them. When fully ripe, plantains are black, with a flavor that some people describe as similar to a banana but not as sweet. Most people prefer them cooked even at this stage.

Source: The Spruce Eats