In veterinary dentistry, the term "tooth resorption" refers to:

Tooth resorption is a condition more commonly seen in cats than in dogs, and it involves the loss of tooth structure as a result of the body's own natural processes. During tooth resorption, the dental hard tissues, including enamel, dentin, and cementum, are destroyed through the action of odontoclasts, which are specialized cells that break down dental tissues. This process can lead to the formation of cavities, exposing the sensitive pulp, causing pain, and potentially leading to infections.

The choice that states "loss of tooth structure" accurately reflects the pathological process occurring during tooth resorption, distinguishing it from other dental issues. For example, tooth decay specifically refers to the cavity formation due to bacterial action, whereas tooth resorption is a systemic response resulting in the progressive destruction of the tooth's structure without the direct involvement of decay-causing bacteria. Extraction of the tooth, while sometimes a necessary procedure after resorption has advanced, is not a definition of tooth resorption itself, and gum disease pertains to a different set of conditions affecting the periodontium rather than the tooth structure directly.