The term "butter unit" can be replaced with several other words. One of the most common is "stick of butter," which refers to the block of butter sold in stick form. Other synonyms for "butter unit" include "butter cube," "butter portion," "butter piece," and "butter pat." In some cases, the context of the sentence may also allow for the use of related terms like "tablespoon of butter" or "ounce of butter." Regardless of the term used, these synonyms all refer to a unit of butter that is commonly used in cooking and baking recipes.