The term "sound barrier" refers to the point at which an aircraft's speed matches the speed of sound, resulting in a sonic boom. However, there are various synonyms for this term that can be used to describe this phenomenon. Some of these synonyms include "sonic wall," "aerodynamic drag," "acoustic barrier," "sonic pavement," and "sound wave resistance." Each of these terms helps to convey the idea of a physical obstacle that sound waves must overcome when an object moves through the air at high speeds. No matter which term is used, they all refer to the same physical phenomenon that has captured the imaginations of people for decades.