The phrase "be an element of" can be replaced by a variety of other terms. One option is "belong to," which implies that the subject in question is a part of a larger group or category. Another synonym is "constitute," which suggests that the subject is an essential component of a system or organization. "Comprise" is another option, indicating that the subject is one of several parts that make up a whole. Finally, "form part of" is a more specific synonym that suggests the subject is a necessary component of a particular entity or structure. Overall, there are many ways to express the idea of something being an element of a larger whole in English.