Lexical scope refers to the visibility and accessibility of variables within different parts of a program. In programming languages like JavaScript or Python, a variable defined inside a function is only accessible within that function and its nested functions. This means that the location where a variable is declared determines where it can be used, creating a clear structure for managing variable access. This concept helps prevent conflicts between variable names and makes code easier to understand. For example, if you have a variable named x inside a function, it won’t interfere with another x defined outside that function. Lexical scope promotes better organization and reduces errors in code.