1. A class of pharmacopeial preparations that are liquid suspensions or dispersions intended for external application; some consist of finely powdered, insoluble solids held in more or less permanent suspension by suspending agents or surface-active agents, or both; others are oil-in-water emulsions stabilized by surface-active agents.
The definition information for lotion is provided by Stedman's. You can search our medical dictionary here.
Stedman's, part of Lippincott Williams & Wilkins, provides a comprehensive line of health-science publications for healthcare professionals and medical students.