What term is used for an opening or break in the skin?

The term that specifically refers to an opening or break in the skin is "ulcer." An ulcer is characterized by a loss of tissue that can occur due to various factors, including pressure, infection, or inflammation. This condition often results in an area where the skin has been destroyed or has lost integrity, leading to a noticeable defect.

In contrast, other terms like abrasion refer to a worn area on the skin that typically results from friction rather than a break. Lesion is a broader term encompassing any pathologic manifestation on the skin, which could include ulcers, but does not specifically denote a break. Wound, while also indicative of some form of skin damage, encompasses both open and closed injuries. Thus, ulcer is the term that specifically denotes a break in the skin due to tissue loss, making it the most accurate answer in this context.