Biodiversity or biological diversity is a neologism and a portmanteau word, from bio and diversity. It is the diversity of and in living nature. Diversity, at its heart, implies the number of different kinds of objects, such as species. However, defining biodiversity or measures of biodiversity, is not so simple. The term biological diversity, was coined by Thomas Lovejoy in 1980, while the word biodiversity itself, was coined by the entomologist E.O. Wilson in 1986, in a report for the first American Forum on biological diversity organized by the National Research Council (NRC). The word biodiversity was suggested to him by the staff of NRC, to replace biological diversity, considered to be less effective in terms of communication. Since 1986 the terms and the concept have achieved widespread use among biologists, environmentalists, political leaders, and concerned citizens world-wide. This use has coincided with the expansion of concern over extinction observed in the last decades of the 20th century.