The branch of sociology that studies the problems of living in cities and towns.

Immediately adjoining an urban area; between the suburbs and the countryside.

(chemistry) Any of several of the condensation products of the reaction between urea and formaldehyde (and their derivatives) used as a thermosetting material.

The exploration of man-made, particularly urban, environments; such exploration in places which are not normally accessible or to which access is prohibited.

A person who explores restricted urban areas such as abandonments, tunnels, roofs, construction sites, etc. Certain non-urban sites can also count, such as mines, quarries, and grain/missile silos.

plural of urban explorer

An infant's instinctive urge to breastfeed. It is a primitive reflex.

(physics) A fissile isotope of uranium, used for energy generation and in atomic weapons, containing one hundred and forty-three neutrons. It has a half-life of 7·038×10⁸ years; it decays into thorium-231 and ultimately lead.

Initialism of undergraduate research assistant.

(software) Initialism of Universal Remote Access.