Of disputed origin:
* possibly from Latin Lupara, a name derived from lupus (“wolf”), as the first fortress of the Louvre was built on a place with such a name designating its area as a wolf hunting den.
* or of Germanic origin, such as Frankish; in an old Saxon-Latin gloss, Loëvar is translated as Castellum, related to Middle Low German lūren (“to watch over, lurk, spy”), from Proto-Germanic *lūraną, which is of uncertain origin, but possibly derived from Proto-Indo-European *lewk- (“to see, shine”).
* possibly from Late Latin roboretum (“oak wood”), from Latin robur (“oak tree”), by analysis with the modern name of the Norman river Rouvre.