Holism (from Greek ὅλος holos "all, whole, entire") is the idea that various systems (e.g. physical, biological, social) should be viewed as wholes, not merely as a collection of parts.[1][2] The term "holism" was coined by Jan Smuts in his 1926 book Holism and Evolution.[3]

The exact meaning of "holism" depends on context. Smuts originally used "holism" to refer to the tendency in nature to produce wholes from the ordered grouping of unit structures.[3] However, in common usage, "holism" usually refers to the idea that a whole is greater than the sum of its parts.[4] In this sense, "holism" may also be spelled "wholism", and it may be contrasted with reductionism or atomism.[5]

The term holistic when applied to diet or medical health refers to intuitive approach to food, eating, or lifestyle.[6] One example is in the context of holistic medicine, "holism" refers to treating all aspects of a person's health, including psychological and societal factors, rather than only his/her physical conditions or symptoms.[7] In this sense, holism may also be called "holiatry".[8] Several approaches are used by medical doctors, dietitians, and religious institutions, usually recommended based on an individual basis.[9][10][11] Adherents of religious institutions, that practice a holistic dietary and health approach, have been shown have longer lifespans than those of surrounding populations, including Ayurveda,[9] Shinto,[12] and the Seventh-Day Adventist Church.[11]