What is the abbreviation used for inch?

The abbreviation for inch is "in." This is a widely recognized standard in both metric and imperial measurement systems. The use of "in" comes from the Latin word "uncia," which means one-twelfth, reflecting that an inch is one-twelfth of a foot. This abbreviation is commonly found in various fields, including engineering, healthcare, and everyday measurements, making it an essential part of understanding and communicating measurements. Other options provided represent different units: "mm" stands for millimeters, "g" stands for grams, and "mcg" indicates micrograms, all of which serve different purposes in measurement but do not refer to inches.