sustainable /səˈsteɪnəbəl/adjective 2noun 1forms 3 adjective2 •Able to be sustained. •Able to be produced or sustained for an indefinite period without damaging the environment, or without depleting a resource; renewable.In addition to the resources listed in the organic and local food sections earlier, a good source of sustainable meat is Heritage Foods USA (heritagefoodsusa.com). — 2008 noun1 •A renewable energy source.It has only been in the last 20 years that the long-term trend away from fossil fuels and toward nuclear energy and sustainables has intensified. — 1996 formssustainables · more sustainable · most sustainable