The number of individuals in a population diagnosed with a specific condition during a specified time is the:

The term that describes the number of individuals in a population diagnosed with a specific condition during a specified time is known as incidence. Incidence refers to the occurrence of new cases of the condition within a given time frame, typically expressed as a rate over a defined period, such as a year. It allows researchers and public health officials to track the emergence of diseases and monitor trends over time.

In contrast, prevalence measures the total number of cases (both new and existing) of a condition in a population at a specific point in time or over a specified period. Rate of the conditions is a broader term that could refer to incidence or prevalence depending on the context, but it doesn't specifically address new cases as incidence does. Duration refers to the length of time individuals experience the condition, which is unrelated to the actual counting of cases diagnosed. Understanding these distinctions is essential for accurately interpreting epidemiological data in public health and research contexts.