**Core Concept**
A flat discoloration on the skin, especially one that is 1 cm in size, is known as a macule. Macules are a type of skin lesion characterized by a change in skin color without any elevation or depression.

**Why the Correct Answer is Right**
The distinction between macules and other types of skin lesions, such as papules, nodules, or plaques, lies in their morphological characteristics. Macules are typically flat and only involve a change in skin color, whereas papules and nodules are elevated above the skin surface. This flat discoloration is due to changes in the concentration or distribution of melanin in the epidermis.

**Why Each Wrong Option is Incorrect**
**Option A:** Macules are not characterized by a raised elevation above the skin surface, making this option incorrect.
**Option B:** Papules are indeed small, but they are also elevated, making this option incorrect.
**Option C:** Plaques are larger than macules and are often associated with inflammation or scarring, making this option incorrect.

**Clinical Pearl / High-Yield Fact**
When describing skin lesions, it's essential to note the morphology, including the size, shape, color, and elevation of the lesion. This will help differentiate between various types of skin lesions and guide further diagnosis and treatment.

**Correct Answer:** . Macule