What term defines diseases capable of being transmitted by contact?

The term that defines diseases capable of being transmitted by contact is "communicable." Communicable diseases are those that can spread from one individual to another, either directly or indirectly. This transmission can occur through physical contact, respiratory droplets, or by touching contaminated surfaces. Examples of communicable diseases include the flu, tuberculosis, and COVID-19, which showcase how easily these infections can move within a population through close interactions and contact.

Other terms like non-communicable refer to diseases that cannot be transmitted between individuals, such as diabetes or heart disease. Vectorborne diseases are transmitted by vectors, typically insects, such as mosquitoes or ticks, and environmental diseases can arise from interactions with contaminated water or soil but do not involve direct person-to-person contact. Thus, the correct answer reflects the fundamental nature of how certain diseases propagate within communities.