expr

-

any expression (dependent on ``form'')

metric

-

an unevaluated name

imp/US

-

unevaluated names

acre

acres

bu

bushel

bushels

chain

chains

cm

cord

cords

feet

foot

ft

furlong

furlongs

gal

gallon

gallons

Gals

gill

gills

gr

hr

ins

inch

inches

kg

km

Lb

lbs

light_year

light_years

mi

Mile

miles

MPG

MPH

ounce

Ounces

oz

Ozs

pint

pints

pole

poles

pound

pounds

quart

quarts

yard

yards

yd

yds