The word 'sustainable' can mean a lot of things, but in the world of fashion, it's more difficult to define. That's why the CFDA and Lexus have teamed up for the EcoFashion Challenge which identifies and celebrates the greatest American designers working in the realm of sustainable fashion.

The CFDA/Lexus Eco-Fashion Challenge was founded in 2010 and has since continued to promote a commitment to sustainable practices and design. This year, the finalists included Alabama Chanin (Natalie Chanin), Erin Snow (Erin Isakov), Kallio (Karina Kallio) Mark Davis, Skin (Susan Beischel), Svilu (Britt Cosgrove & Marina Polo), Titania Inglis.

During at luncheon at ABC Kitchen in New York City, keynote speaker Amber Valetta, dressed in a gorgeous Daniel Silverstein black dress and Manolo Blahniks, spoke about the importance of sustainable fashion. When it came time to announce a winner, designer Natalie Chanin of Alabama Chanin took top prize. Alabama Chanin's upcoming season will be included in the Embody collection on the mezzanine level at ABC Carpet & Home in NYC.

Click through the gallery above to see more photos!