Definition of knell. 1  transitive verb. : 2  to summon or announce by or as if by a knell. 3  intransitive verb. 4  1 : to ring especially for a death, funeral, or disaster : toll. 5  2 : to sound in an ominous manner or with an ominous effect.
For the journal, see Demography (journal) . Demography is the statistical study of populations, including of human beings. As a very general science, it can analyze any kind of dynamic living population, i.e., one that changes over time or space (see population dynamics).
: This scientist studies living organisms and l iving systems. Botanist. : This scientist studies plants. Chief scientist. : This scientist leads other scientists in a particular research area. Ecologist. : This scientist studies the relationship of living things with their living and nonliving. environment. Economist. : This scientist studies economics. Economics is a social science that addresses the production, distribution, and use of goods and services.