||Last edit: 07/Dec/2014
Definitions of many Imperial (and older) units.
Copyright © 1997-2014 All rights reserved
- Unit of area, equal to 4840 square yards. Still very much in use.
- Obscure unit of volume, equal to 24 gallons.
- Unit of length. Three to the inch. A very old measure, not used for
- Barrel (beer)
- Unit of volume, equal to 36 gallons, or 4 firkins. Still in use.
- Barrel (wine)
- Unit of volume, equal to 31.5 gallons. No longer in use
- Barrel (oil)
- A US measure, not English. Equals 42 US gallons.
- British Thermal Unit, or Btu.
- Unit of energy or work
- Obscure unit of volume, equal to 4 gallons.
- Unit of volume, equal to 8 gallons, or 4 pecks. Not in use much at all
these days, but beware that the US bushel is different.
- Unit of volume, usually for wine or beer. Can be 108 or 126 gallons,
depending. No longer used.
- Unit of length, at sea. Defined as 1 tenth of a nautical mile.
- Unit of length, equal to 22 yards, which is the length of a cricket
pitch. When I was at school, we were given such chains to measure things
with - each chain made up of 100 links. There are 10 chains to the furlong.
Not seen much these days, but still seen on not-so-old maps etc.
- Obscure unit of weight, equal to 7 pounds (av.)
- Drachm (fluid)
- Unit of volume, equal to 60 minims. 8 fluid drachms to the fluid ounce.
- Dram [also spelled as Drachm] (avoirdupois)
- Unit of weight. 16 drams to the (av.) ounce.
- Dram [also spelled as Drachm] (troy)
- Unit of weight. Equal to 60 grains. 8 drams to the (troy) ounce.
- Unit of length. Very, very old. The English ell should be taken as 45 inches,
or a yard and a quarter, and the Scots ell is 37 Scots inches, or 72.2 English
inches. Very much not used.
- Unit of length, or rather depth, equal to 6 feet. Still encountered.
- Unit of volume, especially beer. Equals 9 gallons. Extremely popular in pub
- Unit of length. 12 inches, 3 feet to the yard. Very, very common.
- Unit of length, equal to 220 yards, or 10 chains. There are 8 furlongs
to the mile. The name seems to derive from the length of a furrow, somehow.
This unit is still used, especially so in horse-racing.
- Unit of volume. Equal to 8 pints. The Imperial gallon was defined in the
act of 1824 as the volume of 10lb of water at 62°F. Before this, the gallon
was redefined over the years (especially
around the time of the American revolution) with consequent problems for
our colonial cousins, which is why we have 8 of our gallons to one of our
bushels, but the Americans have 9.309177 of their gallons (or 7.751512 of
ours) to one of their bushels. To get around this, they have a dry gallon
and a liquid gallon, which are different. To summarise:
| Imperial gallon||277.4194 cubic inches
| US dry gallon ||268.8025 cubic inches
| US liquid gallon||231 cubic inches
- Unit of volume. Normally taken as a quarter of a pint, it can also be a third
or a half pint, especially in conversation. The legal definition is a 1/4 of a pint.
The word Gill is pronouced with a hard G (as Jill).
- The basic unit of weight in the imperial system. There are 5760 grains to
the Troy pound, and 7000 to the avoirdupois pound.
- Unit of length, or normally height, equal to 4 inches. Still (almost)
universally used in England to measure horses.
- Unit of volume (wine only). 52.5 gallons. Until 1824 it was 63 gallons, a
figure still used by the Americans.
- Horsepower (common)
- A unit of power. Equal to 33000 foot-pound-force per minute. Very much in
- Horsepower (RAC)
- A strange unit, used only to tax cars in the first decades to the 20th
century. It was based on the cylinder diameter, not the swept volume or
power, which seems to have inspired W O Bentley at least to design long-stroke
engines to get them into a lower taxation class.
- Horsepower (misc.)
- There are all sorts of other horsepowers (boiler, metric, electric, metric
etc.) - beware!
- Unit of weight, equal to 8 stones. 20 hundredweight to a ton. This
unit is commonly abbreviated to 'cwt'.
- Hundredweight (short)
- Unit of weight, not much used in England, but apparently used still in the
US. Equals 100 pounds, 20 to the Short ton.
- Very basic unit of length. 12 to the foot. Very much in use.
- Obscure unit of volume, equal to 18 gallons.
- Obscure unit of force - equal to 1000 pound-force.
- Unit of speed or velocity, equal to 1 nautical mile per hour.
Universally used to control the speed of ships and aircraft.
- Very obscure unit of volume - equal to 640 gallons.
- Unit of length. Equal to 3 miles, so a league at sea is different to a
league on land. Much used by poets, but nobody else.
- The abbreviation used for 'pound'. It comes from the Latin word Libra which
translates to 'pound'. This is where the fancy 'L' comes from when talking about the
pound sterling (i.e. the unit of currency in the UK).
- Unit of length. Some authorities (generally American)
say 10 lines to the inch, and some say 12. This seems to be a printing term.
- Unit of length, there being 100 links to a chain. Virtually never seen these days.
- Unit of length. Shown as 1/1000 of an inch in some books, I have never
known anyone use this in England, as a millimetre (an obscure French measure) is known
colloquially as a 'mill'. See thou. However, many friends from
across the Atlantic have pointed out that the mill is very much in use in the US,
for measuring paper, plastic (rubbish bags/garbage sacks etc.) and wire.
- Mile (statute)
- Unit of length, equal to 1760 yards, or 8 furlongs. This unit is
universal in England for measuring distances between places etc., and is
always used on road-signs (eg LONDON 180 miles) and speedometers (as in
miles per hour), and consequently is always quoted by drivers when talking
about fuel consumption (as in miles per gallon).
- Mile (nautical)
- Unit of length, normally at sea or in the air. Originally, the Admiralty
fixed it at 6080 feet. This
unit is universally used by international law by ships and aircraft, as is
the derived unit of the knot.
In the 20th century, an international nautical
mile was defined as 1852 metres, and so you will sometimes see the 6080ft nautical
mile called the British nautical mile.
- Unit of volume. 60 minims to the fluid ounce.
- Obscure unit of length, equal to 2 and a quarter inches.
- Unit of volume - maybe a colloquism. Same as the gill.
This word is quite often used in pubs etc. in certain parts of England, but
not in a technical sense!
- Ounce - avoirdupois
- Unit of weigh, equal to 437.5 grains. 16 drams to the ounce, 16
ounces to the pound. This unit is still very much used in England.
- Ounce - fluid
- Unit of volume, equal to 8 fluid drachms. 20 fluid ounces = 1 pint. This
unit is still used, especially in recipes.
- Ounce - troy
- Unit of weight, equal to 480 grains, or 24 scruples. or 20 pennyweights
or 8 drams. 12 ounces to the pound.Used for weighing bullion, and as an
- Obscure unit of length. Equal to 2.5 feet.
- Obscure unit of length. Equal to 3 inches.
- Unit of volume, equal to 2 gallons. Not much in use these days.
- Unit of weight, equal to 24 grains. There are 20 to the Troy ounce.
- Old unit of length - same as rod and pole. 16.5 feet.
- Unit of volume. The universal measure for beer. There are 20 fluid ounces
to the pint, and 8 pints to the gallon. Different to US pints - beware!
- Old unit of length - same as rod and perch. 16.5 feet.
- Pound - avoirdupois
- Unit of weight, equal to 7000 grains, or 16 avoirdupois ounces.
14 pounds = 1 stone. This unit is still very much used in England.
- Pound - troy
- Unit of weight, equal to 5760 grains, or 12 troy ounces. Used for
weighing bullion, and as an apocatheries measure. The troy pound was
outlawed in 1878.
- Unit of force. There are 32.174 to the pound-force (acceleration to to
gravity being 32.174 feet per second per second).
- Unit of force.
- Unit of pressure - an abbreviation for pounds per square inch.
- Obscure unit of volume - equal to 70 gallons.
- Unit of volume, equal to 2 pints. 4 quarts = 1 gallon. The use of this
unit has declined sharply over the last 20 years.
- Unit of weight, equal to 2 stones. 4 quarters = 1 hundredweight. General
use of this unit seems to have died out around the time of WWII.
- Unit of volume, equal to 64 gallons.
- Unit of length; It is 16.5 feet, which is strange even by English
standards. It is better to define it in terms
of the rood.
- Obscure unit of length - equal to 20 feet.
- Unit of area; an area of 1 furlong long by 1 rod wide, or 1210 square
yards. There are 4 roods to the acre.
- Obscure unit of length - equal to 20 feet.
- Obscure unit of weight, equal to 26 stones.
- Unit of weight. Equals 20 grains. 3 to the Troy dram.
- Scruple (fluid).
- Unit of volume. Equals 20 minims.
- Obscure unit of volume, equal to 64 gallons.
- Strange unit of weight - equal to 32.174 pounds (av.) - see
- Obscure unit of length - equal to 9 inches.
- Unit of weight, equal to 14 pounds (av.). Often used in England
for weighing people. 8 stones = 1 hundredweight. Still quite common in
England, although its use seems to be declining.
- An unofficial unit of length - one thousandth of an inch.
- An obscure unit of weight - same as the quarter.
- Unit of weight, sometimes (especially in the US) known as a long ton. Equals
20 hundredweight, or 2240 pounds. Still very much in use.
- Ton (register).
- Unit of capacity - for measuring ships. 100 cubic feet.
- Ton (short).
- Unit of weight, especially in the US. Equals 2000 pounds, and therefore 20
- Fundamental unit of length. 36 inches (or 3 feet) to the yard, 1760 yards
to the statute mile.
- Yard (of ale)
- This is a drinking glass about 3 feet long, hence the name. It has a wide mouth,
which narrows towards the closed end, where it terminates in a bulb. It is not easy
to drink from! It holds about 2 pints.