The term "chest voice" refers to the lower range of a singer's vocal register, where the vibration is felt in the chest. However, there are several synonyms for this term that singers use to describe this part of their voice. These include "chest register," "full voice," "modal voice," and "normal voice." Some singers also refer to their chest voice as their "normal speaking voice" or use the term "primary register." Regardless of the term used, developing a strong and controlled chest voice is essential for any singer, as it provides the foundation for a full and well-rounded vocal sound.