How is a nodule defined in dermatological terms?

A nodule in dermatological terms is defined as a solid bump that can be felt and is typically at least 1 centimeter in diameter. Nodules are often deeper and more defined than other types of skin lesions, meaning they penetrate more substantial layers of skin, which allows them to be palpable. They can form as a result of various conditions, including infections, inflammation, or neoplasms.

Understanding this definition is important for estheticians when assessing skin conditions or referring clients to dermatologists. A nodule's size and texture usually indicate that it is more than just a superficial lesion, and recognizing this can guide appropriate treatment or care recommendations.

The other options provide descriptions that do not fit the standardized medical definition of a nodule. For example, a freckle is typically a flat, small spot, and thus does not relate to the deeper, solid nature of a nodule. Similarly, while a flat surface raised above the skin describes another type of lesion, it does not convey the solidity or depth associated with nodules. Lastly, a very large vesicle refers to a fluid-filled lesion, which is distinct from the solid characteristic of a nodule.