Final answer:
The abbreviation 'mcg' in a prescription refers to 'Microgram', a unit used to indicate medication dosages. In the given context, 'Synthroid 125 mcg' implies that each Synthroid tablet contains 125 micrograms of the active ingredient.
Step-by-step explanation:
In the prescription written by Mr. Williams, the abbreviation mcg stands for Microgram. Microgram is a unit of measurement commonly used in the field of health and medicine, particularly for indicating the dosages of medication to measure very small quantities of mass. In the metric system, a microgram or microgramme is a unit of mass equal to one millionth (1×10−6) of a gram.
The unit symbol is μg according to the International System of Units (SI); the recommended symbol in the United States and United Kingdom when communicating medical information is mcg.
Therefore, 'Synthroid 125 mcg' means that each tablet of Synthroid contains 125 micrograms of the active ingredient - used for treating conditions like hypothyroidism.
Learn more about Prescription abbreviation