cardo

Cardo is a term with multiple meanings in botany and archaeology, among other uses. In botany, cardo refers to thistle-like plants, especially those in the genera Carduus and related thistles of the Asteraceae family. In many Romance languages, including Spanish and Italian, cardo commonly denotes a thistle. A cultivated relative associated with the term is the cardoon (Cynara cardunculus), whose edible leaf stalks are used in Mediterranean cuisine; cardoon is distinct from true thistles though closely related botanically.

In archaeology and urban history, cardo designates the main north–south street of a Roman city, intended to be the axial spine along which traffic and public life were organized. The term derives from Latin cardo, meaning hinge, a metaphor for a central axis. A city’s perpendicular east–west street is called the decumanus. The cardo maximus often connected major gates, forums, and basilicas and could be aligned with military or ceremonial routes.

The word also appears in other contexts, such as surnames and place names, but the botanical and urban planning senses are the most widely attested in English-language sources. Cardo thus carries significance in both plant terminology and the study of ancient urban design.