Final answer:
A primary lesion not elevated or depressed and less than 1 cm is called a macule, which is a flat, non-palpable area of skin with a color different from the surrounding tissue.
Step-by-step explanation:
A primary lesion that is not elevated or depressed and is less than 1 cm in diameter is known as a macule. Macules represent a change in color and are not palpable since they do not have any thickness. Common examples of macules include freckles, flat moles (nevi), petechiae, and measles. These types of lesions are contrasting from those that are raised above the skin surface, such as papules or plaques, or those that involve a loss of tissue, such as ulcers.