Isn't lībra pondō pleonastic? Because both lībra and pondō meant "weight"?

Question

Isn't lībra pondō redundant, pleonastic and tautological? Because both lībra and pondō meant "weight"? See below!

Wikipedia translates lībra pondō as "("the weight measured in libra"), in which the word pondo is the ablative singular of the Latin noun pondus ("weight")".

Etymology of libra

Janus Bahs Jacquet wrote that libra

originally meant ‘stone’, thence ‘pound weight’ (i.e., the little stone you put on scales to weigh things), thence ‘pound’ (the weight of one of those stones), and only from that was the meaning generalised to mean ‘weight’ in general.

Tim Lymington wrote that librum meant "'weight' as an abstract concept."

"You will also know Libra as the astrological sign, the seventh sign of the zodiac. In classical times that name was given to rather an uninspiring constellation, with no particularly bright stars in it. It was thought to represent scales or a balance, the main sense of libra in Latin, which is why it is often accompanied by the image of a pair of scales."

"It's from Latin libra, an ancient Roman unit of weight, likely from Proto-Italic *liθra."

Etymology of pondō

"pondo in Latin is the ablative of pondus, which is literally 'weight' (ablative being 'by weight')."

How do these quotations below distinguish lībra vs. pondō?

In my research, I stumbled these quotations below. But what do they mean? Are they relevant?

"It makes more sense if you explain that "libra", which meant "balance" is the actual word that came to mean the unit of weight. The "pondo" part precised the weight. "

“a pound by weight” as opposed to a pound by what other measure?

Edit: why the downvotes? Turns out there’s a mass pound as well as a weight pound, plus the English currency Pound.

Answer 1

Libra pondo means “weighing a libra,” and yes, it is redundant. We can see this because while we can see Romans writing things like:

• argenti decem pondo libras habere (A. Gellius)
• libram pondo aeris valere (Varro)

⋯ we also see many cases where they only say libra or only pondo:

• libra ocellatorum (Varro; an ocellatum is apparently some kind of gem or die)
• corona aurea librarum quinque (Suetonius)
• auri quinque pondo (Cicero)
• argenti pondo viginti millia (Caesar)

Let us look at the words individually:

• libra is the name of a Roman unit of weight, which is around 326 g (estimations for the exact value vary a few grams up and down). It is usually translated as “pound” (as are Romance words derived from it, e.g. French livre). It does not mean “weight” per se, but it generally unequivocally refers to a weight, so we do not necessarily have to specify that we are talking about weight.

• pondo is not, as Wikipedia says, simply “the ablative singular of the Latin noun pondus,” because that would be pondere. It is indeed understood as stemming from an ablative singular, but it is usually parsed as an adverb meaning “weighing, by weight.” As such, in principle, it has to go along with some quantity, e.g. libra pondo.

  However, if no unit is specified, it works as an undeclinable noun meaning pound or pounds. In effect, when a Roman says “gold weighing five” (auri quinque pondo), he means “five pounds of gold” (circa 1.6 kg). And this was a very common way to talk about weights. The English term “pound” (and others, e.g. German „Pfund“) are derived from it.

The way you phrased your question – isn't libra pondo pleonastic – suggests you are surprised the Romans would have used a redundant expression. But redundancy is very common throughout human speech. After all, “a bag weighing 5 kg” is also redundant, as the kilogram is a unit of weight, and it would suffice to say “a bag of 5 kg.”