A museum is an institutional space open to the public on a regular basis for non-commercial educational or entertaining cultural exhibitions. This usage is applied to museums which have not been categorized in the museum sub-categories, such as fine arts or natural history museums.

Galleries where paintings are sold are not listed as museums, although spaces for temporary exhibits are, as long as the purpose of the exhibit is aesthetic or instructional rather than commercial.

Botanical exhibits of live plants, zoological exhibits, planetariums, and libraries are each assigned to their own usage categories.