1. A distinct area within a city: This is the most common interpretation. A sub-city could be a large neighborhood, a commercial district, or a specific area with a unique identity, sometimes with its own infrastructure and governance. For example, "Downtown" or "Midtown" in many cities could be considered sub-cities.
2. A smaller city within a larger metropolitan area: This is more common in areas with sprawling metropolitan regions. For example, a town or municipality that's closely linked to a larger city could be called a sub-city.
3. A self-contained area within a city, typically with its own amenities: This could be a planned development, a business park, or even a university campus. The key characteristic is that it has its own infrastructure and services to support its residents or workers.
4. A concept for urban planning: Some urban planners use "sub-city" to describe a specific type of urban development that focuses on sustainability, community engagement, and a mix of housing, commercial, and cultural spaces.
Examples:
* Dubai Marina: A large, self-contained area in Dubai with its own marina, residential towers, hotels, and shopping malls.
* West End in London: A large district within London known for its theaters, restaurants, and shops.
* Satellite cities: Towns or cities surrounding a larger city that are connected by transportation and economic ties.
Ultimately, the meaning of "sub-city" depends on the specific context and the person using the term. If you're unsure, it's always best to ask for clarification.