Sunflower seed is the fruit of Helianthus annuus. There are three common types of sunflower seeds: linoleic acid (the most common), high oleic acid and nusun developed for sunflower oil. Each variety has its own unique monounsaturated, saturated and polyunsaturated fat content. The information in this paper mainly relates to linoleic acid varieties.

For commercial purposes, the patterns on the shells of sunflower seeds are usually classified. If the shell is pure black, the seed is called black oil sunflower seed. This crop can be called oil sunflower crop. These seeds are usually pressed to extract their oil. Striped sunflower seeds are mainly used for food. As a result, they can be called candy sunflower seeds.

When the term "sunflower seed" is applied to a seed in its pericarp (shell), it is actually the wrong name. In Botany, it is a small plant. After shelling, the edible residue is called sunflower kernel or sunflower kernel.