Cities : Glossary

There are 23 documents in this section.


  • Infrastructure

    31 August 2001

    "The basic equipment, utilities, productive enterprises, installations and services essential for the development, operation and growth of an organization, a city or a nation" (Abrams, Charles, 1971, The Language of Cities: A Glossary of Terms, The Viking Press, New York). The term 'infrastructure' is often used in a more restricted sense to refer to the built facilities that link buildings and human activities - including transport infrastructure, infrastructure for water, sanitation and drainage, power stations, and telecommunications systems. It is sometimes used to include health and educational facilities. The dividing line between infrastructure and services is often unclear - for instance water pipes are generally considered infrastructure but water vendors are not; roads are infrastructure but buses are generally not.

  • Local Agenda 21

    31 August 2001

    The term Local Agenda 21 comes from Chapter 28 of Agenda 21, the document formally endorsed at the UN Conference on Environment and Development (also known as the Earth Summit) in Rio de Janeiro in 1992. This Chapter recognises that the successful implementation of most aspects of sustainable development depends on competent and effective local authorities. Local Agenda 21s are the local plans for environment and development that each local authority is meant to develop through a consultative process with their populations, with particular attention paid to involving women and youth.

  • Migration

    31 August 2001

    Usually defined as the permanent change of residence of an individual or a group. Immigration and emigration refers to permanent changes of residence that cross national boundaries while in- and out-migration refer to such changes within national boundaries. Virtually all urban centres have complex patterns of in- and out-migration, and worldwide, natural increase accounts for more of the growth in urban population than net in-migration.

  • Urban environment

    31 August 2001

    The physical environment in urban areas, with its complex mix of natural elements (including air, water, land, climate, flora and fauna) and the built environment. Its quality is much influenced by its geographical setting; the scale and nature of human activities within it; the wastes, emissions and environmental impacts that these generate; and the competence and accountability of the institutions elected, appointed or delegated to manage it.

  • Urban centre

    31 August 2001

    A concentration of people, buildings and economic activities which meet the criteria set by the government in its definition of what constitutes an 'urban centre'. Most governments define urban centres in one of three ways: population thresholds; population thresholds combined with other criteria (for instance the proportion of the economically active population in non-agricultural activities); and administrative or political status. There is no agreement about what population threshold to use; some nations classify all settlements with more than a few hundred inhabitants as urban while others use thresholds of 10,000 or 20,000 inhabitants.

  • Urbanisation

    31 August 2001

    A process driven by net rural-to-urban migration through which an increasing percentage of the population in any nation or region come to live in settlements that are defined as 'urban centres'. The level of urbanisation is the percentage of the population living in urban areas. Populations tend to urbanise as their per capita income increases, since increasing proportions of the economic base are in industrial or service sectors, most of which are based in urban areas. The term 'urbanisation' is also used for the process by which agricultural, forest or other 'rural' land gets built over by urban areas or converted to other urban uses.

  • Ecology

    16 March 2001

    Originally defined by Ernst Haeckel in 1866, ecology is the study of the relationships that develop among living organisms and between these organisms and the environment.

  • Conservation (nature)

    9 March 2001

    Protection against irreversible destruction and other undesirable changes, including the management of human use of organisms or ecosystems to ensure such use is sustainable.

  • Water-washed diseases

    22 August 2000

    Diseases spread from one person to another due to inadequate supplies of water for personal hygiene. These include infections of the skin and eyes (e.g. trachoma) and infections carried by lice, e.g. louse-borne epidemic typhus.

  • WHO (World Health Organisation)

    22 August 2000

    A UN agency created in 1948 to deal with global health issues and to achieve as high a level of physical, mental and social well-being as possible for peoples of the world. It is involved in a variety of environemental studies, including the impact of climate change and ozone depletion on health, in conjunction with other agencies such as the World Meteorological Organisation (WMO) and the United Nations Environment Program(UNEP).