Dear Luisma,
I have previously shown how Iberian uses the number "five"
(bos/boist/borst(e))
to express an indeterminate number.
This effect is found only in inscriptions and not in toponyms, as
far as I know.
A number of Iberian toponyms, however, incorporate lau(r) "four",
which may have a similar function (and it is also found in a few
personal names).
There are at least four (!) instances of Lauro - Llerona,
Catalonia, Laury near Valencia, Lora de
Estepa, Andalucia, and the present-day Lauro, Bizkaia.
This could well indicate a plot of land the size of four units of
measurement, rather like the English Fivehyde, Fivehead,
Fyfield, etc, and have nothing to to with indeterminate
quantity.
However, Luaron Akron (Cape Carvoeira, Portugal), is surely
*lau-arri "many rocks", and Loarre, Upper
Aragon, may well be identical.
Then there is Lautulae, a defile between Tarracina and
Fundi, in Latium south of Rome. This would appear to be *lau-tulo
"many holes".
And there is the River Lowther in Cumbria, UK. This was Lauther
1160, Louther 1278 (Lauder in Scotland is the
same). The name may well represent an earlier *lau-turri "many
springs", and probably refers to the numerous natural springs
in the Lowther Valley. (Peg Huck's Pond, in the grounds of Lowther
Castle, is named after one of my relatives.)
And there is also Lautrego, the old name for Lautrec, east
of Toulouse. This was probably *lau-turri-ko "of the many
springs".
With best wishes,
Angus J Huck