CDR is carbon dioxide removal - activities that remove CO2 from the atmosphere and durably store (or Sequester) it in geological, terrestrial, or ocean reservoirs, or in products. CDR includes enhancement of biological or geochemical sinks and direct air capture (DAC) and storage [suggesting engineered chemical or physical processes], but excludes natural CO2 uptake not directly caused by human intervention.
source: J Wilcox, B Kolosz, & J Freeman (2021) CDR Primer; Concepts