simple past tense and past participle of sustain

Held continuously at a certain level. / (music) Held at a certain pitch.

(transitive) To maintain, or keep in existence. / (transitive) To provide for or nourish. / (transitive) To encourage or sanction (something). / (transitive) To experience or suffer (an injury, etc.).

(music) A mechanism which can be used to hold a note, as the right pedal on a piano.

Able to be sustained. / Able to be produced or sustained for an indefinite period without damaging the environment, or without depleting a resource; renewable.

A renewable energy source.

(ecology) A means of configuring civilization and human activity so that society, its members and its economies are able to meet their needs and express their greatest potential in the present, while preserving biodiversity and natural ecosystems, planning and acting for the ability to maintain these necessary resources for future generations.

In a sustainable manner.

present participle of sustain

The process by which something is sustained or upheld.