An action or activity that balances the emission of carbon dioxide or other green gases into the atmosphere.

“A carbon offset credit is a transferrable instrument certified by governments or independent certification bodies to represent an emission reduction of one metric tonne of CO₂, or an equivalent amount of other GHGs” – Carbon Offset Guide

A carbon offset is any activity that compensates the emission of carbon dioxide (CO₂) or other greenhouse gases (measured in carbon dioxide equivalents [CO₂e]) by providing for an emission reduction elsewhere” – Britannica