Another area where we use Celtic vocabulary every day without being aware of it, is the names of places and waters in the region. Thus all large and even many small rivers bear names that are handed down to us from or through Gaulish.
The Celts have not always been the initiators of these names, but inherited some of them from Indo-European:
- Moselle, Mosel, called Mosella by the Roman historian, Tacitus (c. AD 100), is probably a diminutive of Mosa, the name of the river Maas or Meuse. This can be explained as coming from Indo-European *mod-sā- "dripping, flowing (= river)", from the o-grade of Indo-European *mad- "be wet, drip, flow".
- Saar, first mentioned by the Roman poet and statesman Ausonius (4th century AD), who calls it Saravus, which is perhaps related to Indo-European *ser- "reddish" (cf. the headstream "Rote Saar") or *ser- (?)/ *sreu- "to flow".
- Prims, in a document of the year 949 Primantia, belongs to Indo-European *bhrem- and probably means the "buzzing, roaring river".
Some rivers gave their names to settlements right on the waterfront as e.g.
- Lösterbach, the first element of which is from Indo-European *lū-starā- "muddy, dirty (stream)", as well as Losheim, attested as Losma in 897, Losema in 1098, from *Lu-samā "(settlement on the) muddy, dirty stream".
- Wadern, Wedern and Wadrill belong together. Wadern is recorded as Waderella around 950, the other as Waderola in 981. They derive from Indo-European *vedor-, more precisely *vodrā, which was extended to *Vodrellā in Gaulish or Gallo-Roman. The names simply mean "water" (or a specific kind of water) and "(settlement on the) water".
Besides bodies of water, places took their names from other landscape features:
- Kell, Callido in a record of the 10th century, from Gaulish *kall-ēto- "(settlement in the) wood", cf. Old Irish caill, Welsh celli "grove, wood".
- Kaisen, around 1200 Caisen, from Gaulish *kassano- "oak", which also yielded French chêne.
- Zewen, in the 11th century still Cebennamons, from Gaulish cebenna "mountain ridge", which is also the basis of the French Cévennes.
Other places are named after the founders or owners of estates:
- Merzig from Gaulish Marciācum (attested in 802) "settlement of Markos or Marcus". The personal name could be Gaulish Mărkos or Latin Mārcus.
- Tincrey (arr. Château-Salins, France) goes back to Gaulish *Tincoriācum, deriving from Tincorius, a Romanised form of the plain Gaulish Tincorix, probably a variant of Tancorix "'peace-king', peaceful (one)".