What condition is described as a crack or split in the skin?

The term used to describe a crack or split in the skin is "fissure." A fissure is characterized by a narrow, linear opening that can occur in various areas of the skin, often as a result of dryness, inflammation, or trauma. This condition is commonly seen in places where the skin is subjected to regular stretching or movement, which can lead to the skin's surface breaking.

Erosion refers to the loss of part of the epidermis, typically leading to a moist lesion, but it does not specifically represent a split or crack. A scar is a mark left on the skin after a wound has healed, indicating tissue repair rather than an actual crack. An ulcer is an open sore or lesion that can penetrate deeper into the skin or underlying tissues, which is distinct from a crack or split. Thus, the precise definition of a fissure makes it the accurate answer to the question.