Glossary of terms

Here you will find definitions of terms used in resources on the Foodsource website. You will also find these definitions on the right-hand side within chapters. If you have any suggestions for new glossary items, let us know here.

2 (1) | A (12) | B (5) | C (16) | D (4) | E (8) | F (12) | G (4) | H (3) | I (6) | L (5) | M (12) | N (6) | O (4) | P (9) | R (8) | S (9) | T (1) | U (2) | W (4) | Y (1) | Z (1)

Subsistence farming

Subsistence farming refers to rearing animals and growing crops only for your own consumption, without having any surplus to take to market as a source of cash income.

Substitution effect

In economics, the substitution effect refers to the idea that as prices increase or as a product becomes scarce, people will replace such items with substitutes that are cheaper or easier to access. In the context of diets, substitution effects refer to the changes in the environmental footprint of a person's diet, according to the relative impact of foods that are substituted for one another.

Sustainable intensification

is a recently developed concept that is understood in different ways by its critics and supporters. A common understanding is that it denotes the principle of increasing or maintaining the productivity of agriculture on existing farmland while at the same time, reducing its environmental impacts. Understood in this way, SI designates a goal for the development of agricultural systems but does not, a priori, favour any particular agronomic route to achieve it. It may involve the intensification of different types of agricultural inputs (e.g. of knowledge, biotechnologies, labour, machinery) and apply these to different forms of agriculture (e.g. livestock or arable; agroecological or conventional). Forms of intensification that can be called sustainable intensification must lower environmental impacts and land use, relative to yields. However, for some, to merit the term ‘sustainable’ social, economic, and ethical criteria must also be considered.

System boundaries

The subjective boundaries that define what is included within the system under analysis (and so counted) and what is external to the system (and so not counted). System boundaries have multiple dimensions, including what stages are focused on (e.g. production, distribution), what inputs and outputs are measured (e.g. land, greenhouse gases), what geographic locations are included, and more.


Turbidity refers to the amount of light that can pass through water (i.e. its cloudiness), as a result of particles that are suspended within the fluid. It can vary naturally depending on location, but can have detrimental impacts on ecosystems if cause by human activity. For this reason, it is often used as an indicator of water quality.

Ultra-processed food (UPF)

Sometimes used loosely to refer to snacks and fast foods, ultra-processed food generally refers to one of the four categories of the NOVA food classification (see below). NOVA describes UPFs as ‘industrial formulations’ of food products, typically mass-produced, that contain few ‘natural’ ingredients. Advocates of NOVA point out that UPFs consist of many additives and food-derived ingredients such as whey, protein isolates and invert sugar, which are produced and combined through processes that are uncommon in domestic kitchens. They understand these foods to be designed so as to be so appealing that they displace the consumption of healthier, less processed foods, thereby generating high profits for their manufacturers. Foods in the UPF category include biscuits, mass-produced buns and breads, sweetened cereals, margarines and spreads, packaged snacks, ice cream, flavoured yogurts, soft drinks, powdered meals, ready-made meals, and instant sauces and stocks. Proponents of the concept have argued that the consumption of UPF is the primary driver of the global ‘pandemic’ of overweight and obesity, while contributing to non-communicable diseases such as metabolic syndrome and certain cancers. It has been argued that the production and consumption of UPFs undermine social and environmental sustainability while perpetuating unequal power dynamics in the food system. Opponents of the concept have contested these claims. They argue that the concept is imprecise and groups together foods with different nutritional characteristics.


Deficiencies of a particular component of food, usually due to insufficient intake and/or absorption of that component. This usually refers to energy (often measured in calories) or macronutrients (such as protein, carbohydrates, or fat), but can also refer to micronutrients (vitamins or minerals).

Water footprints

Water footprint is a metric that quantifies the amount of water used to produce each of the goods and services we use. It allows these goods and services to be compared in terms of their water impact, and so to the impact on limited water resources of consumption by individuals, organisations, and even nation states. Water footprints incorporate all the water used – i.e. unable to be used again due to evaporation or removal in products – across the full lifecycle of a produce from production through to consumption, including all inputs to production (e.g. feed crops used in pork production). It has three components: (1) green water - rainwater used in soils; (2) blue water - freshwater sources; (3) grey water - water amount needed to dilute pollution to safe levels.


The World Health Assembly is the forum through which the World Health Organisation is governed.

Wildlife-friendly farming

while this is a fairly informal term, it generally refers to an approach to farming that aims to support both food production and the conservation of biodiversity on farmland. Wildlife-friendly farming is associated with the use of reduced chemical and fertiliser inputs and the preservation of native vegetation (e.g. flowers, trees, and bushes) on or around farmland. Those who use the term tend to equate wildlife-friendly farming with a land sharing approach. Related although not synonymous terms include organic farming and agroecology.

World Health Organisation

The World Health Organisation is a specialised branch of the United Nations. It is dedicated to improving public health worldwide.

Yield gap

this is the difference between the actual productivity of a given area of farmland and the maximum productivity that could in principle be achieved using agricultural practices, resources and technologies that are currently available. The best yields that can be obtained locally depend on the capacity of farmers to access and use, among other things, land, seeds, water, nutrients, pest management, soils, biodiversity, and knowledge. Yield gaps are studied and measured at various scales - from the farm through to the national and global levels.

Zoonotic diseases

Zoonotic diseases are pathogens (e.g. viruses, bacteria, funghi, parasites) which can – to varying degrees – be transmitted between animals and human. Examples include bird and swine flu, lyme disease, bovine tuberculosis, rabies, and zika.