pound - kilogram, gallon - ?

LITRE
List of words for the clue pound - kilogram, gallon - ? from the crossword:
UNIT LITER EZRA TONNES MASS PINTS PINT QUID QUART YARD MILE METRE KILOMETRE INCH OUNCE PENCE KILO TUNS STETSON
WordClue
ACREkilogram - pound, hectare - ?
INCHkilogram - pound, centemetre - ?
MASSsecond - time, kilogram - ?
MILEkilogram - pound, kilometre - ?
TIMEkilogram - mass, second - ?
UNITkilogram or gallon
YARDkilogram - pound, metre - ?
METERmass - kilogram, distance - ?
METREpound - kilogram, yard - ?
PENNYunit of currency in various countries
POUNDlitre - gallon, kilogram - ?
QUARTunit of volume
GALLONkilogram - pound, litre - ?
SECONDmass - kilogram, time - ?
HECTAREpound - kilogram, acre - ?
DISTANCEkilogram - mass, meter - ?
KILOGRAMgallon - litre, pound - ?
STERLINGpound
KILOMETREpound - kilogram, mile - ?
CENTEMETREpound - kilogram, inch - ?
HECTAREpound - kilogram, acre - ?
CENTEMETREpound - kilogram, inch - ?