Pronunciation: (ek"stur-nal'i-tē), [key]
1. the state or quality of being external.
2. something external; an outward feature.
3. excessive attention to externals.
4. an external effect, often unforeseen or unintended, accompanying a process or activity: to eliminate externalities such as air pollution through government regulation.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.