pound - kilogram, acre - ?

HECTARE

List of words for the clue pound - kilogram, acre - ? from the crossword:

UNIT ROO LITER EZRA ROOD TONNES MASS EEYORE ROODS QUID YARD MILE METRE KILOMETRE INCH GALLON CENTEMETRE PENCE KILO

Word	Clue
ACRE	kilogram - pound, hectare - ?
INCH	kilogram - pound, centemetre - ?
MASS	second - time, kilogram - ?
MILE	kilogram - pound, kilometre - ?
TIME	kilogram - mass, second - ?
UNIT	kilogram or hertz
YARD	kilogram - pound, metre - ?
LITRE	pound - kilogram, gallon - ?
METER	mass - kilogram, distance - ?
METRE	pound - kilogram, yard - ?
PENNY	unit of currency in various countries
POUND	hectare - acre, kilogram - ?
QUART	unit of volume
GALLON	kilogram - pound, litre - ?
SECOND	mass - kilogram, time - ?
DISTANCE	kilogram - mass, meter - ?
KILOGRAM	yard - metre, pound - ?
STERLING	pound
KILOMETRE	pound - kilogram, mile - ?
CENTEMETRE	pound - kilogram, inch - ?
STERLING	pound
LITRE	pound - kilogram, gallon - ?