Definitions

1. noun

A unit of area in the International System of Units (SI), equal to 10^-28 square meters or 10^-32 square centimeters.

“The nuclear cross-section is typically given in millibarns for small-angle scattering.”

2. noun

A unit of area used in particle physics to measure the cross-section of an interaction.

“The scattering cross-section was found to be 3 millibarns.”