The word "pothole" can be split into two distinct morphemes. The first part being "pot," a word derived from Middle English that means "a deep hole," and the second part being "hole," which maintains the same meaning today, that is, a hollowness in the ground.
Both of the morphemes in the word "pothole" indicate some sort of opening in the ground, which is what "pothole" means today. "Pot" may also mean something of cylindrical shape, such as pots used for cooking. If this is the true etymology, "pothole" means a cylindrical hole. Although the words "pot" and "hole" were commonly used separately, they were not used together in the word pothole until the early 20th century.