The dependent or response variable is the output which is measured to find the effect of changing the values of independent/input variable(s). In the equation Y=f(x), Y is the dependent variable and one or more X's are the independent variable(s).
The end product or outcome of a process is usually the dependent variable and the various activities or inputs going into the making of the product or service are the independent variables. For instance:
Customer satisfaction score is a dependent variable, for which the possible predictors are perceived quality of the product/service, ease of doing business, staff responsiveness, etc.
Sales performance of the sales staff is an outcome variable dependent on inputs such as number of sales calls put in, time spent with clients, etc.
When constructing a scatter plot or regression plot, the dependent variable is placed on the vertical (Y) axis and an independent variable is placed on the horizontal (X) axis.