Final answer:
A parameter is a special variable in programming that holds the value of data passed to a function when it is called.
Step-by-step explanation:
A parameter is a special variable that receives a piece of data when a function is called. In the context of programming, when a function is defined, it can be given one or more parameters, which are placeholders for the data that will be passed to the function when it is called. This data that gets passed is often referred to as an argument. Each parameter within the function definition is a variable that holds the value of the corresponding argument passed during the function call.
For instance, in an equation of a line, such as y = mx + b, the variables x and y can be seen as parameters of the equation with m representing the slope and b representing the y-intercept. These variables, when given specific values, determine the position and shape of the line on a graph.
Variables are essential in various disciplines, including mathematics and programming. In mathematics, variables like x and y represent quantities that vary along the axes. In programming, variables also assume various values, but in the context of function parameters, they have a specific role in holding the data passed to functions.