Relying on someone or something else for support or existence. The young child is dependent on her parents for food and shelter.
Contingent upon or determined by something else. The success of the project is dependent on the team's ability to work together.
Grammar: subordinate; unable to stand alone and requiring another element for complete meaning. In the sentence "When she arrived, we ate dinner", "When she arrived" is a dependent clause.
Addicted to or controlled by the use of a drug or other substance. The clinic supports people who are dependent on alcohol and drugs.