What keyword is used to define a variable in JavaScript that can be reassigned?

The keyword used to define a variable in JavaScript that can be reassigned is "let." This keyword allows for block scope and provides more control over the variable's scope compared to "var," which is function-scoped and can lead to unexpected behavior due to hoisting.

Using "let" signifies that the variable can be changed after its initial declaration. This is particularly useful in situations where the value of the variable needs to vary, such as within loops or conditionals.

While "const" is used to define variables that are immutable (i.e., cannot be reassigned), "let" provides the flexibility needed for dynamic values. Thus, in scenarios where you expect to assign a variable multiple times throughout your code, using "let" is the appropriate choice.

The term "define" is not a valid keyword in JavaScript for variable declaration, which further emphasizes why "let" is the correct answer in this context.