Skip to Content


Pronunciation: barn

Definition: A unit of area for effective cross-section of atomic nuclei with respect to atomic projectiles; equal to 10−24 cm2.

[fr. “big as the side of a barn” by humorous comparison with much smaller areas]

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

© Copyright 2018 Wolters Kluwer. All Rights Reserved. Review date: Sep 19, 2016.