Which measurement is equivalent to grain?

The correct measurement equivalent to grain is the abbreviation "Gr." A grain is a unit of weight commonly used in pharmacology and medicine to measure ingredients in medications. The abbreviation "Gr" specifically denotes this unit, making it clear and universally recognized within clinical settings.

Understanding this measurement is crucial for healthcare professionals who need to calculate dosages accurately. The grain is historically one of the oldest units of measure, particularly in the context of pharmaceuticals, where precision is vital for patient safety.

The other measurements provided are not equivalent to a grain. "Gtt" refers to a drop, typically used for liquid medications. "Oz" stands for ounces, which measure volume, and "Lb" refers to pounds, also a unit of weight, but significantly larger than a grain. Each of these units operates in different contexts and scales, highlighting the importance of understanding the correct applications of various units in medication dosing.