There are several synonyms for the term "Spanish Onion". The term can be used to describe a type of onion that is typically larger than usual, with a sweeter flavor and matte exterior. Other terms that are used interchangeably with "Spanish Onion" are torpedo onion, red onion, and Vidalia onion. Torpedo onions are similar to Spanish onions in size and taste, but they are longer and more narrow. Red onions are smaller and have a reddish-purple hue to their exterior. Vidalia onions are another sweet onion variety that is known for its mild flavor and tan-colored exterior. Regardless of which term is used, these onions are a popular addition to many dishes and can be found in most grocery stores.