Gallon (US)
The US gallon, symbol gal, equals 4 quarts, 8 pints, or 128 fluid ounces (~3.785 liters). Its origins trace to English wine and ale measures but were standardized in the US in the 19th century. Gallons are used for beverages, fuel, and large-volume recipes. While metric liters are the dominant unit of measurement in most countries, gallons remain widely used in the United States for everyday and industrial liquid measurements.
Teaspoon (Metric)
The metric teaspoon equals 5 milliliters, standardized to simplify cooking and medical measurements in countries that use the metric system. Unlike the US teaspoon, the metric teaspoon is slightly larger (5 mL vs ~4.92892 mL) and is widely used in recipes, pharmaceutical dosing, and nutrition labeling. Its simplicity ensures consistency across recipes and instructions internationally.