- Situated nearer the base of a pyramidal organ in relation to a specific reference point; opposite of apical.
- In dentistry, denoting the floor of a cavity in the grinding surface of a tooth.
- Denoting a standard or reference state of a function, as a basis for comparison. More specifically, denoting the exact conditions for measurement of basal metabolic rate (q.v.); basal conditions do not always denote a minimum value, metabolic rate in sleep is usually lower than the basal rate but is inconvenient for standard measurement.