Legal Definitions - tertium quid

The term tertium quid is Latin for "a third thing." In a legal context, particularly in Scots law, it refers to a new entity or concept that arises from the combination or interaction of two existing components, but possesses qualities or characteristics that are entirely distinct and different from either of the original components alone. It is not merely a blend or an average of the two, but something fundamentally new and unique.

Here are some examples to illustrate this concept:

• The Smartphone: Before smartphones, people used mobile phones for communication and personal computers for computing tasks. The smartphone emerged as a tertium quid. It wasn't just a phone with a small computer inside, nor was it merely a portable computer that could make calls. Instead, it created an entirely new category of device, integrating advanced computing power, internet connectivity, a vast ecosystem of applications, and multimedia capabilities into a single, highly portable form factor. Its unique functionalities and user experience were distinct from both its telephone and computer predecessors.

• Ride-Sharing Services: Traditional taxi services provided on-demand transportation with professional drivers and company-owned vehicles. Private car ownership offered personal mobility. Ride-sharing platforms like Uber or Lyft represent a tertium quid. They combine elements of both but create a fundamentally new service model. They leverage private car owners as drivers and connect them with passengers via a digital platform, introducing dynamic pricing, peer reviews, and a decentralized network. This new model is distinct from both the regulated, fleet-based taxi industry and the simple act of owning a car, offering a unique form of urban transportation.

• Fusion Cuisine: Consider the culinary style known as Tex-Mex food. It originated from the blending of traditional Mexican cuisine and the regional cooking styles of Texas. However, Tex-Mex is a tertium quid; it is not simply Mexican food served in Texas, nor is it merely American food with Mexican influences. It has developed its own distinct identity, with unique dishes (like chili con carne, fajitas, or nachos), flavor profiles, and ingredient combinations that are characteristic of neither parent cuisine alone, but rather a new and separate culinary tradition.