v.1. To be contingent upon something or someone for an outcome: Whether or not we go on the picnic depends on the weather.
2. To rely on something or someone, especially for support or maintenance: Children depend on adults for food and shelter.
3. To place trust or confidence in someone or something: You can depend upon my honesty.
4. To have a chronic or compulsive need for something; be addicted to something: As time went by, he began to depend on painkillers to get him through the day.