Definition:Avoirdupois/Quarter/Historical Note

Historical Note on Quarter (Avoirdupois)
The word quarter was in common use (and probably still is) in the domestic context, in societies using imperial measurements of mass, to mean a quarter of a pound, that is, $4$ ounces.

This particularly applies to old-fashioned retailers of confectionery to children.

It should be clear from the context whether a quarter of a pound or a quarter of a hundredweight is under discussion.