Ad idem is a Latin phrase that means "to the same point" or "of the same mind." It is commonly used in legal contexts to describe two parties who agree on a particular point or issue. There are several synonyms for ad idem, including "in agreement," "of one mind," "on the same wavelength," "of the same opinion," "united," and "in consensus." These terms all convey the idea of two or more parties being in alignment or agreement on a particular topic. They can be useful in both formal and informal contexts, such as negotiations, discussions, or simply expressing agreement with someone.