[kgwgk]

You have misunderstood the wiktionary entry:

> Du latin lībra (« poids d’une livre »)

tells you just that the meaning of the latin word is a measure of weight (a pound).

There is no way that can be interpreted as "the weight of a book" (that would be « poids d’un livre »).

[umanwizard]

Oh shit! I read it as "un".