Multis is a prefix that means "many" or "multiple". There are countless synonyms for this word, depending on the context in which it is being used. For example, if you are talking about a company that operates in many different countries, you might use the term "multinational". If you are describing a book or movie that has multiple storylines, you could use the word "multilayered". Other synonyms for "multis" include "multifaceted", "multipurpose", "multivarious", "multidimensional", and "multiform". No matter what you are trying to convey, there is likely a synonym for "multis" that will help you do so with precision and clarity.