Ad lib: Abbreviation for the Latin "ad libitum" meaning "at pleasure" and "at one's pleasure, as much as one desires, to the full extent of one's wishes." Sometimes seen on a prescription or doctor's order. For example, during an overnight fast when the patient is not to eat any food but can have water, the doctor's order might read: "Water ad lib" (water as desired).
Subscribe to MedicineNet's Women's Health Newsletter
Women's Health Resources
Last Editorial Review: 5/13/2016