Nucleophilic Addition:
Definition
Like the name of the reaction suggests, nucleophilic addition includes the addition of a nucleophile to a molecule.
This is a distinguishing reaction for ketones and aldehydes and the nucleophile will add to the electrophilic carbon atom of the carbonyl group. The nucleophile can be a negatively charged ion like cyanide / hydride, or it can be a neutral molecule like water / alcohol.