Wiktionary
n. A large, defended Iron Age settlement associated with the Celtic La Tène culture.
Wikipedia
An oppidum (plural oppida) is a large fortified Iron Age settlement. Oppida are associated with the Celtic late La Tène culture, emerging during the 2nd and 1st centuries BC, spread across Europe, stretching from Britain and Iberia in the west to the edge of the Hungarian plain in the east. They continued in use until the Romans began conquering Europe. North of the River Danube, where the population remained independent from Rome, oppida continued to be used into the 1st century AD.
Usage examples of "oppidum".
Magna copia frumenti comparata considunt Drappes et Lucterius non longius ab oppido X milibus, unde paulatim frumentum in oppidum supportarent.
Itaque productis copiis ante oppidum considunt et proximam fossam cratibus integunt atque aggere explent seque ad eruptionem atque omnes casus comparant.
Interim Gaius Caninius legatus, cum magnam multitudinem convenisse hostium in fines Pictonum litteris nuntiisque Durati cognosceret, qui perpetuo in amicitia manserat Romanorum, cum pars quaedam civitatis eius defecisset, ad oppidum Lemonum contendit.