Aitken nucleus
noun
Ait·ken nucleus ˈāt-kən- 
meteorology
: a microscopic aerosol particle in the atmosphere that encourages condensation to gather into a droplet
Using air samples collected from a 65-foot tower in a eucalyptus forest in Portugal, the researchers found an abundance of tiny aerosols, known as Aitken nuclei, that could only have been produced locally.
Henry Fountain, New York Times, 3 Nov. 1998
Henry Fountain, New York Times, 3 Nov. 1998
Word History
Etymology
after John Aitken †1919 Scottish meteorologist and engineer
First Known Use
1906, in the meaning defined above