Key terms & definitions

The substance formed when oxygen combines with haemoglobin in red blood cells.

A combination of apparently contradictory words, such as “warm ice”.

A gas made of three oxygen atoms per molecule, O₃, which forms an ultraviolet-absorbing layer in the upper atmosphere.

A gas whose molecules contain three oxygen atoms, $\mathrm{O_3}$. Ozone in the atmosphere absorbs ultraviolet radiation and helps protect life on Earth.

An action regarded as sinful or wrong, producing negative karmic consequences.

The Pan Africanist Congress, an anti-apartheid organisation that organised the anti-pass protest at Sharpeville in March 1960.

The speed at which events or information unfold for the reader.

An implanted electrical device that helps control an abnormal heart rhythm.

A group of cells in the right atrium that controls the natural resting heart rate.

The speed at which change takes place.

The rhythm created by the duration of shots and the frequency of transitions between them.

Bringing an area under control by ending or suppressing resistance. It does not necessarily mean that its inhabitants willingly accepted Roman rule.

The belt around the Pacific Ocean where many active volcanoes and earthquakes are concentrated.

The belief that war and violence are wrong.

The principled rejection of war as a way of resolving conflict, often accompanied by opposition to violence more generally.

A holiday sold for a combined price covering travel and accommodation, rather than requiring the customer to arrange each separately.

A holiday in which transport and accommodation are sold together, usually by a tour operator.

A bonded, multilayer packaging material whose constituent materials provide different properties, such as stiffness, moisture resistance and barriers to light or oxygen.

A unit of data sent across a network, containing data and information needed to deliver it.

Relating to non-Christian religious beliefs or practices; Puritans used this description for customs with pre-Christian roots.

A mobile stage used to perform plays at stopping places along streets.

The Lakota name for the Black Hills, a region especially sacred to the Lakota Sioux.

A business model in which users pay an initial price for an app or game and can also make purchases within it.

A medicine that relieves pain or other symptoms without killing the pathogen causing an infectious disease.

A medicine that relieves pain, a symptom of disease, without killing the pathogens causing an infection.

A coloured coating that protects a surface and usually conceals much of the material beneath it.

Two values belonging to the same person, object or observation, one for each variable.

A preference test in which a tester compares two food samples and chooses the one they prefer.

A pair consisting of the force of object A on object B and the force of object B on object A, produced by one interaction.

A pair of elements whose order does not follow increasing relative atomic mass because the chemically appropriate order is the reverse.