“sustain”

To help keep from falling.

A foodstuff, a type of food.

To remain in a particular place, especially for a definite or short period of time; sojourn; abide.

A (usually self-sustaining) chemical reaction involving the bonding of oxygen with carbon or other fuel, with the production of heat and the presence of flame or smouldering.

A level of effort beyond what one can usually sustain; great exertion.