A dependent is the variable where the research is done for. It is the variable that might change due to changes in the independent variable.
Examples of dependent variables
Examples make it more easy to understand what dependent variables are. I will give you three.
Income, age of marriage, hours spend in the kitchen, may be different for male and female. Now three dependent variables can be identified: income, age of marriage, hours spent in the kitchen are the dependent variable and gender is the independent variable.
A second example: when a student attends a course changes in knowledge could happen. So the dependent variable is knowledge and the change (if any) might be due to attending the course which is the independent variable.
In a third example the health of a person (dependent variable) might be related to the hours spent on sport (independent variable).
A depedent variables needs to have an independent variable
It is obvious that a dependent variable is always part of a combination. There must be an independent variable too. You can read more about it on our page Experimental variables.
A dependent variable can be measured at a nominal, ordinal, interval or ratio scale. This is another way to classify variables, and this is explained elsewhere in this dictionary. You must know both classifications, because both determine the type of analysis that you can perform with these variables. Read all about it in my paper called How to choose the correct statistical test?