1. To provide someone, or something, whatever is needed to exist, to continue, etc.: There is not enough oxygen to sustain, or to support, life at very high altitudes.
2. To keep something in position by holding it from below: The roof, unable to sustain the weight of all the snow, collapsed.
3. To keep someone going with emotional or moral support: Hope sustained Jim's family during that difficult time when the tornado hit his area.
4. To manage to withstand something and to continue in spite of it: The volunteers sustained their efforts to help the those who were in the flooded areas of the typhoon.
5. To experience a setback, injury, damage, loss, or defeat: The soldier sustained several broken bones while the army was sustaining heavy losses.
6. To make something continue to exist: The actors were sustaining the audience's interest for a long time.
7. To confirm that something is true, correct, or valid: The medical report sustains the claims of those who were injured in the car accident.
8. Etymology: from Latin sustinere, "hold up, keep up, support, endure"; from sub, "from below" + tenere, "to hold".