An example of sustain is for a foundation to support the house.
An example of sustain is to survive days without food or water.
The beams sustain the weight of the roof.
The judge has sustained the prosecutor's objection.
Sustain an effort.
The income needed to sustain a family.
We were sustained by her unflagging optimism.
Can't sustain the blistering heat.
Sustained minor injuries.
To sustain a mood.
To sustain a verdict.
A foundation sustains the superstructure; an animal sustains a load; a rope sustains a weight.