NLP (Natural Language Processing) is a branch of Artificial Intelligence that enables computers to understand, interpret, and process human (natural) language.
Source: Chapter 6, Unit Overview
For a 1-mark question, one clear definitional sentence is sufficient. Examiners look for two key ideas: (1) it is an AI technique, and (2) it deals with human/natural language understanding and processing. Avoid listing applications or stages — that exceeds the mark allocation.