There are several synonyms for the term "X Chromosomes." One of the most commonly used synonyms is the "female chromosome" as it is present in individuals with female reproductive systems. The X chromosome is paired with the Y chromosome to determine an individual's biological sex, with two X chromosomes representing the female sex and one X and one Y chromosome representing the male sex. Other synonyms for the X chromosome include "homogametic chromosome" and "autosome." Understanding the significance of the X chromosome is essential in studying genetics, as it carries numerous genes involved in a variety of biological processes and diseases.