<p><strong>Noun:</strong></p><ul><li>the state or quality of being dense; compactness; closely set or crowded condition.</li><li>stupidity; slow-wittedness; obtuseness.</li><li>the number of inhabitants, dwellings, or the like, per unit area: The commissioner noted that the population density of certain city blocks had fallen dramatically.</li><li>Physics: mass per unit volume.</li><li>Electricity: the quantity of electricity per unit of volume at a point in space, or the quantity per unit of area at a point on a surface.</li><li>the degree of opacity of a substance, medium, etc., that transmits light.</li><li>Photography: the relative degree of opacity of an area of a negative or transparency, often expressed logarithmically.</li><li>Computers: a measure of the compactness of data saved on a storage medium, as disk or tape, or displayed on an electronic screen.</li></ul>