Hydroponic: a method of growing plants in water rather than in soil

Source: http://www.merriam-webster.com/dictionary/hydroponic

“BrightFarms, which finances, builds and operates such ventures, is spending about 4 million to construct a 100,000-square-foot hydroponic greenhouse on a roof in Sunset Park, Brooklyn”. from Gotham farmers sprout cash crops by Adrianne Pasquarelli

I now understand the usage of the word hydroponic, because in the quote above it explains how the seeds will be grown which is a method where seeds will be grown in water as opposed to soil.