What term describes a small lump on the skin?

The term that describes a small lump on the skin is "nodule." A nodule is a solid, raised area of tissue that can vary in size and is often found beneath the surface of the skin. These lumps can be formed due to various reasons, such as infection, inflammation, or growth of abnormal tissue.

In contrast, a fissure refers to a split or crack in the skin, often resulting from dryness or irritation, and does not describe a raised lump. A lesion is a broader term that encompasses any change in tissue, which can include nodules but also other types of skin changes such as sores or tumors. Keratin is a protein found in the skin, hair, and nails, which does not pertain to lumps or growths on the skin.