A "paradigm shift" refers to a fundamental change in the underlying assumptions or practices within a particular field or discipline. This concept, popularized by Thomas Kuhn in his book "The Structure of Scientific Revolutions," illustrates how scientific progress often occurs through revolutionary changes rather than gradual evolution. When a new theory or model emerges that better explains observations, it can replace the existing framework, leading to a significant transformation in understanding. These shifts can occur in various areas, including science, technology, and social norms. For example, the transition from Newtonian physics to Einstein's theory of relativity represents a paradigm shift in our understanding of space and time. Similarly, the rise of the internet has transformed communication and information sharing, marking a significant shift in how society interacts and operates.