Final answer:
In medicine, 'gtt' is an abbreviation for 'drop', used in prescription dosages to indicate that a medication should be administered in drops.
Step-by-step explanation:
The abbreviation gtt stands for 'drop' and is used in medical prescriptions to indicate the dosage of a liquid medication. In practice, it specifies that the medication should be administered drop by drop, with the number of drops often defined by the physician. For example, if a prescription says '2 gtt q4h', it means the patient should take two drops of medication every four hours.