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A glossary of science-related words.

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A biomineral produced by various types of mollusc that is made predominantly from calcium carbonate and the carbohydrate chitin. Known as ‘mother of pearl’, it gives the inner shell of the mollusc its characteristic lustrous and iridescent appearance.


A nanoparticle in which atoms form an ordered, repeating pattern, with characteristic surface ‘faces’.


A very thin layer, less than 100 nm thick, coating another material.


Are materials having particles or constituents of nanoscale dimensions.


Nanometre (nm) is a billionth of a metre.


A particle that has at least one dimension of 100 nm or less. Nanoparticles tend to have different properties to the same material at a larger size.


Refers to dimensions below 100 nm. Also refers to the small size, often only a few nm, at which the properties of a substance are different to properties of bulk material.


The study of atoms, molecules and objects whose size is on the nanometre scale (1–100 nanometres).


Nanotechnology is about understanding and applying the science of the ultra-small. It explores the special properties of stuff at the nanoscale (1–100 nanometres; 1 nanometre is a billionth of a metre) and uses them to make new materials and devices.


A hollow cylinder only a few nanometres wide, made of one element, normally carbon.


A species that lives naturally in a country, as opposed to species that have been introduced by the activity of humans. Species can be a native of more than one country, for example, mānuka is native to both New Zealand and Australia.

natural selection

An evolutionary process where heritable traits that arise through mutation give an organism a higher chance of survival in their environment and become more common in a population as these organisms have a higher likelihood of reproducing.

nautical mile

A unit of length used by sea and air navigators. By international agreement, it has been set at 1852 metres (about 6076 feet) – slightly longer than a mile.


A cloud of dust or gas in space. Some nebulae are where stars are being born, others are thrown off by dying stars.


A sugary liquid found in many flowers, made and stored in a nectary. Used to attract animals, which eat it and accidentally collect or deposit pollen at the same time.

nerve gas

Chemicals that interfere with the action of the nervous system and can cause death. They have been classified as weapons of mass destruction, and as such, their production and stockpiling is illegal.


The study of brain function in animals.


A research area in medical science that is concerned with the interactions of the brain and the gut.


Relating to the nervous system. Symptoms of neurological disorders include paralysis, muscle weakness, poor co-ordination, loss of sensation, seizures, confusion, pain and altered levels of consciousness.


A medical professional skilled in the diagnosis and treatment of disease of the nervous system.


Nerve cell.


A particle that makes up the nucleus of an atom and has no charge. Because it is smaller than an atom, it is usually referred to as sub-atomic.


Immune cells that form a primary defence against bacterial infection.


The unit of measurement of a force (N), named after the famous English physicist Sir Isaac Newton whose laws of motion and gravity underpin much of modern day physics.

Newtonian fluid

A fluid that maintains constant flow rate regardless of the amount of stress applied.


The position occupied by an organism in an ecosystem. The niche includes both the organism’s specific physical environment and the role that it plays within the wider ecosystem.


A chemical composed of three oxygen atoms for every nitrogen atom. They can leach into water from fertiliser run-off and can be harmful in aquatic environments.


A class of chemical compound where nitrogen is bonded to metal or some non-metal elements. Some of the hard, tough advanced ceramics used as bearings are nitrides, for example, silicon nitride (Si3N4).


Part of the nitrogen cycle. A process that takes place in the soil where bacteria convert ammonium into nitrites and then nitrites into nitrates.

nitrification inhibitor

A chemical that prevents nitrification taking place. It prevents the conversion of ammonium to nitrate by inhibiting the enzyme activity in microbes responsible for this process.


A non-metal – symbol N, atomic number 7. Nitrogen is essential for life. It is an important part of many cells and processes such as amino acids, proteins and DNA.

nitrogen compound

A compound that has nitrogen (N) in it. Some examples are dinitrogen gas (N2), ammonia (NH3), nitrite (NO2-), nitrate (NO3-) and nitrous oxide (N2O).

nitrogen cycle

The process by which nitrogen passes through the ecosystem.

nitrogen oxide

N2O. One of the six greenhouse gases identified under the Kyoto Protocol.

nitrous oxide

N2O. A naturally occurring atmospheric gas. It is used as a mild anaesthetic and as a fuel. It is also a greenhouse gas.

Nobel Prize

An annual, prestigious international award for achievement in physics, chemistry, physiology or medicine, literature and peace.

noble gas

Gases in Group 18 of the periodic table, often called inert gases. They are not very reactive due to the stability of their electron structure.


Any unwanted or distracting sounds. Used in science to describe randomly combined sounds from many different sources.


A system of names, terms or symbols used by a particular group. Science has many examples of nomenclature, such as chemical compounds, classification and taxonomy, and mineral groups among others. The arts, the legal system and other disciplines also have their own nomenclature.

non-coding DNA

The components of an organism’s DNA sequences that do not encode for protein sequences


The technique used does not require the patient's body to be entered by incision, or any samples taken.


A chemical element that forms acidic oxides and is a poor conductor of heat and electricity (e.g. sulfur).

non-Newtonian fluid

A fluid that changes in flow rate depending on the amount of stress or length of time that stress is applied.

normal fault

A fault in which the block of earth on one side falls relative to its surroundings.

North Pole

The North Pole is thenorthernmost point on the Earth, lying diametrically opposite the South Pole.

nose cone

The front end of a rocket or other vehicle that comes into contact with the air first. It is shaped to reduce aerodynamic drag.

Nothofagus spp.

The collected species of the Nothofagus genus, or southern beech trees. In New Zealand, the southern beech forests are an important ecosystem, which contains the honeydew insect. These forests consist of a range of species of the southern beech.


New or unusual in an interesting way.


The part of a rocket engine consisting of a narrow throat and an exit cone through which high-speed gases escape from the combustion chamber.

nuclear chemist

A scientist who studies radioactive elements, including their structure and reactions. Some nuclear chemists study the effect of radiation on living things.

nuclear fission

A nuclear reaction in which an atomic nucleus, especially a heavy nucleus such as an isotope of uranium, splits into fragments. Usually, two fragments of comparable mass are produced along with several neutrons. A large amount of energy is released during the process.

nuclear fusion

The process by which multiple atomic particles join together to form a heavier nucleus. This process is accompanied by the release or absorption of energy. The Sun produces heat and light by the nuclear fusion of hydrogen atoms into helium atoms.

nuclear radiation

High energy particles or rays emitted during the nuclear decay processes.

nuclear reaction

A reaction that involves a change in the composition of a nucleus and can evolve or absorb an extraordinarily large amount of energy.

nuclear reactor

A system in which controlled nuclear fission reactions generate heat energy on a large scale, which is subsequently converted into electrical energy.


The process by which heavier chemical elements are synthesised from hydrogen nuclei in the interiors of stars.


The building block of DNA. It includes one base, one phosphate molecule and one sugar molecule.


1. The very small, very dense, positively charged centre of an atom containing protons and neutrons. 2. Part of the cell that contains the cell’s hereditary information and controls the cell’s growth and reproduction.


Different atomic forms of all elements, in contrast to isotopes, which refer only to different atomic forms of a single element.


A naturally occurring substance with a beneficial affect on human health.


A food substance needed for growth, energy provision and other body functions.

nutrient cycling

The movement and exchange of organic and inorganic matter back through and between living organisms and their physical surroundings, i.e. soil, water, atmosphere. The ecological recycling of nutrients.

nutrient planning

A term used by farmers when determining the type and quantity of nutrients needed for their farms. Such planning avoids excess nutrients, minimising nutrient loss through leaching and run-off.

nutrient run-off

Nutrients, especially excess nutrients from fertiliser applications on pastures and from livestock dung, are carried by surface or ground water and flushed into waterways. This can cause eutrophication.


The study of interactions between genes and food.