The term "only one" means something that exists or occurs in a singular form. Some synonyms for "only one" include unique, sole, solitary, singular, and one-of-a-kind. These terms are often used to describe people, objects, or situations that are distinct or exceptional. For example, if someone says they have the "only one" of a particular item, they mean that it is the only one of its kind. Alternatively, if someone describes a person as "one-of-a-kind" or "unique," they are expressing admiration for that individual's qualities or attributes. The use of synonyms for "only one" adds precision and variety to everyday language.