Vegetable Oil is a triglyceride extracted from a plant. These oils have been part of human culture for millennia. The term "vegetable oil" can be narrowly refers only to substances which are liquid at room temperature, or in the broader sense regardless of the state of matter of a substance at a given temperature. Thus, vegetable oils that are solid at room temperature are sometimes called vegetable fats. Vegetable oils comprise triglycerides, in contrast with waxes glycerin lacking in structure. Although many parts of plants can produce oil, in commercial practice, mainly oil is extracted from seeds.