externality

noun

ex·​ter·​nal·​i·​ty ˌek-ˌstər-ˈna-lə-tē 

plural externalities

1

: the quality or state of being external or externalized

2

: something that is external

3

: a secondary or unintended consequence

pollution and other externalities of manufacturing

Examples of externality in a Sentence

Recent Examples on the Web

The wealth stored in that home can vanish in an instant, and rebuilding takes years—and even then, the rebuilding process could be subject to changes in the environment, legal and regulatory decisions, and other externalities. —Dave Birnbaum, Forbes, 22 Feb. 2025

This is where the administration doesn’t do a good job taking externalities into account. —Rhonda Richford, Footwear News, 3 Sep. 2019

Moreover, considering the wide-ranging positive externalities of anti-ageing, governments are likely to provide various types of public funding and support for the field. —Abdo Riani, Forbes.com, 23 Apr. 2025

Truly smart regulation could include something like a methane speeding ticket slapped on those who are spewing the gas too freely into the atmosphere and have the financial means and moral obligation to eliminate externalities. —Antoine Rostand, Time, 21 Apr. 2025

Word History

First Known Use

1673, in the meaning defined at sense 1