The word 'voluminal' is derived from the word volume and is used to describe something that has a large volume or occupies a large space. However, there are many other synonyms that can be used to describe the same thing. Some of these include voluminous, spacious, capacious, roomy, extensive, commodious and ample. These words can be used interchangeably depending on the context of the sentence. For instance, a large room can be described as voluminous or spacious while a product that has a large serving size can be described as ample or capacious. Overall, understanding the synonyms of 'voluminal' can help to improve one's writing skills and vocabulary.