Data are said to be discrete if there can be no value between two plausible values.
Many social demographics are measured on a discrete scale. For example, the number of days since birth, household size, the number of children, and the number of clinical consultations made in the past year.
In health and medical sciences, the use of discrete variables is also common. For example, the number of adverse events since the start of a new medication, number of medication errors, and follicle count.