There are several synonyms for the term "smaller nipple." One common phrase is "hypoplastic nipple," which refers to a nipple that is underdeveloped or smaller in size than normal. Another term is "micro nipple," which signifies a nipple that is extremely small. "Undeveloped nipple" is another term used to describe a nipple that is not fully formed or developed. Additionally, "flat nipple" may be used to refer to a nipple that is not raised or protruding, which can sometimes make it appear smaller than normal. Regardless of the term used, all of these indicate a nipple that is smaller than average in size.