In common usage, a collection is any group of items that has one or more properties in common. For example, paintings from the same artist, or coins from Germany before 1900, see collecting and collectible.
... the town. The population density is 2,391.2/km² (6,199.1/mi²). There are 3,883 housing units at an average density of 789.1/km² (2,045.6/mi²). The ...