This short 35-minute module addresses the basic terms and concepts relating to food and nutrition, malnutrition, food security and livelihoods. By the end of this module, you will be able to define and differentiate these key concepts and understand the different situations that they encompass. Understanding these concepts is indeed very important in order to be able to assess the nutrition situation, to design and implement programmes, investments and policies that address nutrition problems (also called "nutrition-sensitive"), and to evaluate the nutritional outcomes of programmes, investments and policies.