Terms to watch out for

can: to be able

may: expressing uncertainty, or to be possible

might: expressing strong uncertainty

cancer: a malignant neoplasm

neoplasm: a blanket term referring to an uncontrolled growth of abnormal cells in either humans or animals. Neoplasms may be benign (do not invade surrounding tissues or spread to other parts of the body) or malignant (invade surrounding tissues and spread to new sites in other parts of the body)

tumour: a neoplasm that forms an abnormal solid mass of tissue (in contrast to neoplasms such as leukaemia, which do not form tumours). Tumours can be benign or malignant

These 2 spellings are usually used interchangeably (in Australia and other English-speaking countries). However, in some specialist publications (notably the national, state and territory departments of agriculture), a distinction in meaning is made between the spellings:

• carcase: the body of an animal that has been slaughtered for meat (e.g. at an abattoir)
• carcass: the body of an animal that has died from natural causes, including disease or injury.

See carcase, carcass

Both these terms are a sign of weak and passive constructions:

Avoid these constructions and improve your writing by activating the verbs that are hiding as nouns:

See also Balancing active and passive voice

case–control study: an observational study design in which the history of a group of participants with a specific outcome (e.g. a disease) is compared with the history of a matched group without the outcome – for example, comparison of the previous drinking habits of people with cancer and people without cancer

cohort study: an observational study design in which a cohort of participants with a specific treatment, exposure or condition is followed over a period and compared with a matched group with a different treatment, exposure or condition – for example, comparison of the long-term outcomes of cohorts of children brought up in areas with and without fluoride in the drinking water

cell cycle: the period from one cell division to the same point in the next

cell division: the formation of 2 cells (daughter cells) from one cell (parent cell)

See cell cycle, cell division

See cell strain, cell line

cell strain: cultured tissue cells that will not divide indefinitely. Cell strains only divide a limited number of times before they die (referred to as the Hayflick limit)

cell line: cell cultures of specific human or animal cells that will divide indefinitely, provided they are maintained properly. Cell lines have escaped the Hayflick limit and are immortal

Celsius: relating to the temperature scale in which water freezes at 0 degrees Celsius (0 °C) and boils at 100 °C at standard atmospheric pressure (760 mmHg); the temperature on the Celsius scale is the temperature in kelvins minus 273, and a degree Celsius is equal to a kelvin. Named after the Swedish astronomer Anders Celsius

centigrade: the historical name for the Celsius temperature scale. Named from the Latin (centum = 100, gradus = steps)

See Celsius, centigrade

characteristic: a property of an item; subtly different from a parameter (see below) because parameters define function – for example, colour is a characteristic of a car or train, but does not affect function

parameter (general): limits or boundaries of a system (eg the parameters of the project)

parameter (mathematics): a measurable factor (variable or constant) that defines a system. For example, a steam train and an electric train have different parameters for creating motion. In either case, speed is a variable (see below)

variable (general science, research): an attribute of a system. Some variables have only 2 possible values (yes/no; on/off) and are called binary, or dichotomous variables; some variables can have any of a range of values (eg age, height) and are called continuous. One of the most important elements of the scientific method is the isolation of different variables, subjecting one to experimentation by varying it while controlling the others

variable (mathematics): a symbol that represents an unknown quantity in a mathematical expression (compared with a known quantity, or constant)

climate change: the long-term change in Earth’s weather patterns. Although the term is often used to refer to anthropogenic climate change – that is, caused by human activities, such as burning fossil fuels and mass deforestation – Earth system events, such as volcanic eruptions and tectonic plate movements, also contribute to climate change

climate variability: the year-to-year change seen in regional weather; should not be used interchangeably with climate change

global warming: the increasing average global air temperature that is associated with climate change

global change: planetary-scale changes in atmospheric circulation, ocean circulation, climate, the carbon cycle, the nitrogen cycle, the water cycle, sea ice, sea level, food webs, biological diversity, pollution, health and so on

greenhouse effect: the process by which radiation from a planet’s atmosphere warms the surface of the planet to a temperature above what it would be in the absence of an atmosphere. Anthropogenic climate change is sometimes referred to as the enhanced greenhouse effect

See climate change, climate variability, global warming, global change, greenhouse effect

climate: the weather conditions prevailing in an area in general, or over a particular period

weather: the temperature and conditions of cloudiness, dryness, sunshine, wind, rain and so on, at a particular place and time

clinical study: observational study design for making epidemiological observations of the effects of different clinical treatments or exposures on comparable cohorts or selected groups of people. The most common observational study designs are cohort studies and case–control studies

clinical trial: an experimental design for directly comparing clinical effects in human participants who are allocated to groups that receive different treatments – for example, to compare a drug treatment with a placebo. The most rigorous clinical trial design is the randomised controlled trial, in which participants are randomly allocated to the treatment groups

See clinical study, clinical trial

cloning (general): replicating and propagating the genetic makeup of an organism, either partially or completely. There are several different types of cloning (see below)

clone (cell culture): a population of cells derived from a single cell by cell division (mitosis). The clone is seen as a clump of cells in the cell culture dish. The cells in a cell culture clone are not necessarily identical

clone (plants): may refer to a cultured clone (as above), or to a group of plants derived by propagation from a single individual through cuttings or other asexual means

clone (bacterial): the unicellular progeny of a single bacterial cell. When grown on agar in petri dishes, bacterial clones form clusters (colonies)

molecular or DNA cloning: copying a particular sequence of DNA, and transferring it to a different cell (usually bacterial or yeast) using a DNA vector (usually a plasmid, phage or similar), where it is copied along with the rest of the cell’s DNA when the cells divide. This method can be used to produce large quantities of the product of the DNA sequence (e.g. to produce insulin). See also Recombinant DNA technology

cloning (animals): a type of reproduction in which the complete genotype of an animal is copied, generally by replacing the nuclear DNA of an egg cell from a host with the nuclear DNA of a body (somatic) cell from the donor organism (a process called somatic cell nuclear transfer). ‘Dolly’ the sheep was created in this way

therapeutic cloning: a method to obtain perfectly matched human embryonic stem cells from an individual. These cells have the potential to become tissue-specific cells that can be transplanted back into the individual to repair damaged cells or tissues without risk of rejection. The technique involves somatic cell nuclear transfer – the same technique that created Dolly the sheep – but the cloned egg cell containing the individual’s DNA is only allowed to form a small cell cluster (blastocyst), the inner layer of which is rich in stem cells. These stem cells are removed and used to create the specific cell type(s) required

See case–control study, cohort study

Australia, which is a federation of the states and territories, is officially the Commonwealth of Australia. Commonwealth is often used to refer to national institutions such as the government and the parliament. However, because of the potential for confusion with the Commonwealth of Nations (the British Empire), Australian should generally be used in place of Commonwealth. References to legislation are the main context requiring use of Commonwealth, which should always have an initial capital:

communicable disease, transmissible disease, infectious disease: a disease (such as one caused by a bacterium, virus or prion) that can spread from person to person, from animal to animal, between nonhuman animals and people, or from the environment to nonhuman animals or people, by direct or indirect means (e.g. via an insect vector). Communicable is more commonly used for human diseases than for animal diseases

contagious disease: a disease that spreads from person to person, from animal to animal, or between nonhuman animals and people, by direct contact with the infected individual or their secretions

infective animal or person: an animal or person who is at a stage of an infection at which they are able to spread the infection to others

noncommunicable: a disease or condition that is not spread among animals or humans, such as diabetes

transmissible: capable of being spread either directly (e.g. via contact or air) or indirectly (e.g. via a vector)

comparable: able to be compared (ie having features in common), or worthy of comparison

similar: resembling

If two things closely resemble each other, it is preferable and less ambiguous to describe them as similar, rather than comparable.

compare with: consider similarities or differences between 2 or more items

compare to: liken to

See compare to, compare with

complement (general): to go well together, to make complete

complement (biology): proteins in blood plasma that interact with antibodies to activate an immune response

compliment: to express praise (verb), or an expression of praise (noun)

See complement, compliment

comprise: to consist of or contain

compose, constitute: to make up

See biodegradable, compostable, recyclable

See compose, comprise, constitute

See amount, concentration, level

condition: a general term for diseases, lesions and disorders; often excludes mental health, where disorder is preferred (e.g. Diagnostic and statistical manual of mental disorders)

disease: a condition that impairs the normal function of a person, plant or animal. Diseases can be communicable (spread to a person from an animal, the environment or another person – e.g. measles, HIV, malaria, influenza) or noncommunicable (caused by environmental or genetic factors – e.g. cardiovascular diseases, cancer, diabetes, chronic respiratory diseases)

disorder: a synonym for disease (i.e. a functional abnormality), used for noninfectious conditions such as physical, metabolic or mental conditions; in mental health, mental disorder is preferred to mental illness

illness (sickness): a synonym for disease but often used to indicate the person’s experience of a disease (i.e. a person can have a disease without being ill or sick)

syndrome: the occurrence of several associated medical signs, symptoms or other characteristics (e.g. Down syndrome)

See also Disease names

congenital: a symptom or condition that one is born with (e.g. a congenital heart condition). Congenital conditions can be caused by either hereditary or environmental factors

genetic: relating to an organism’s DNA or genes (e.g. genetic code), or a mutation in an organism’s DNA or genes

genetics: the study of genes and heredity

See compose, comprise, constitute

consumer: a person who is receiving health care assistance for any reason (i.e. including people who are not actually unwell, such as a person having a baby or a person having a routine screening test). Changing use of patient to consumer also reflects a change in the relationship between people seeking health care advice or assistance and those providing the care, to one of a more equal partnership

patient: a person who is receiving health care. This term has the additional implied meaning that the person is unwell or sick; hence it has been replaced in many contexts with the term consumer

See communicable, contagious, infectious, infective, noncommunicable, transmissible

contamination: a hazardous substance such as a toxin, disease agent or radioactive material; exposure of an individual or the environment to such a substance; introduction of such a substance into water, air or soil at a concentration that makes the water, air or soil unsuitable for its intended use (also applies to surfaces of objects, buildings and products)

pollution: substances such as vehicle emissions and wastes that cause damage to the environment or adverse health effects; introduction of such substances to the environment

continual: frequently repeated

continuous: continuing without a break

See continual, continuous

convergence: commonness in structures that have evolved independently. For example, the ability to fly is present in many types of animals that do not share a common evolutionary heritage

homology: commonness in structures or genes through evolution of species with a common ancestor. For example, wings in flying mammals, flippers in swimming mammals and forearms in primates are homologous

vestigiality: property of a trait that has been retained throughout evolution but has lost its function – for example, the coccyx (tailbone) in humans

Criteria is the plural of criterion.

See criteria, criterion

These terms all refer to killing animals. Some have implications about the nature or purpose of the procedure:

• euthanase: to subject to euthanasia – literally ‘a good death’; often used to emphasise that the animal was killed humanely
• slaughter: often used to mean killing of an animal to produce meat for human or animal consumption.

Cull and sacrifice are best avoided because they are euphemisms. Of the other terms, the one chosen should be used consistently throughout a document to avoid confusion.

cultivar: a plant that has been bred for particular characteristics

hybrid: a plant that has been derived by cross-breeding of 2 plants of different species

variety: an international taxonomic rank below species for algae, fungi and plants

plant variety: a legal term for a cultivated plant that provides its breeder with some legal protection (so-called plant breeders’ rights). This term should not be confused with the international taxonomic rank of variety