"The other half" is a phrase commonly used to refer to the opposite or missing part of something or someone. However, there are several synonyms that can be used to express the same meaning. For instance, "the remainder" is generally used to refer to the remaining part or quantity of something. "The second half" or "the latter half" can be used to describe the last part of a sequence or a game. Similarly, "the counterpart" is used to indicate a corresponding person or thing. "The complement" can refer to a part that completes or adds to something else. In short, these synonyms can be useful in expressing the intended meaning of "the other half" in different contexts.