Definition

1. Noun:
   • A unit of volume: An "imperial gallon" is a specific unit of measurement for capacity, used in the British Imperial System. It is legally defined as exactly 4.54609 litres. It is used for measuring both liquids and dry goods.

Usage

• The "imperial gallon" is a standard unit. It is different from the smaller US liquid gallon (approximately 3.785 litres).
• It is commonly abbreviated as gal.
• It is used in countries that employ or have historically employed the Imperial system, such as the United Kingdom, Canada, and some Commonwealth nations.

Examples

• Noun:
  • The car's fuel efficiency is rated at 35 miles per imperial gallon.
  • The recipe calls for one imperial gallon of milk.
  • In the UK, petrol is sold by the litre, but fuel economy is still often discussed in miles per imperial gallon.

Advanced Usage

• "imperial gallon" vs. "gallon": In an international or technical context, specifying "imperial gallon" is crucial for clarity, as the unqualified term "gallon" can refer to different volumes (e.g., US gallon, imperial gallon).
• Historical Context: The imperial gallon was standardized in the British Weights and Measures Act of 1824, replacing earlier gallon measurements.

Variants and Related Words

• Gallon (gal): The general term, which requires context (US or imperial) for precise meaning.
• Quart: A unit of volume equal to one quarter of an imperial gallon.
• Pint: A unit of volume equal to one eighth of an imperial gallon.
• Litre (Liter): The metric unit of volume; 1 imperial gallon ≈ 4.54609 litres.

Synonyms

• UK gallon: A common informal synonym.
• British gallon: A common informal synonym.

Related Phrases

• Miles per gallon (mpg): A common measure of fuel efficiency, where the "gallon" refers to the imperial gallon in countries using that system.
• Gallons per mile (gpm): The inverse of mpg, sometimes used to express fuel consumption.

Noun

1. a British imperial capacity measure (liquid or dry) equal to 4 quarts or 4.545 liters