Nursing theory and models provide a framework for nursing practice and the development of specialized nursing knowledge. Theories are conceptual frameworks that describe, explain, and predict phenomena related to nursing. They consist of concepts, definitions, relationships, and assumptions. Models demonstrate how theories can be applied in practice. The nursing metaparadigm defines the major concepts of nursing as the person, environment, health, and nursing. Nursing theories are important as they guide practice, provide a basis for research, and enhance communication within the profession.