A vicenarian is a person who is between the ages of 20 and 29. There are various synonyms that can be used to describe a person in this age group. These include "twentysomething", "twenty-something", "young adult", "millennial", "generation Y", and "youth". Each of these words conveys the idea of a person who is still in the early stages of adulthood, with the world at their feet and much to explore and discover. While the term "vicenarian" may not be used as frequently as these other words, it is still a useful term for discussing this specific age group.