Actinic (solar) Keratosis
A pre-cancerous skin growth usually caused by sun exposure. The growth begins as a flat, scaly area that later develops a hard, wart-like surface. If left untreated, this condition can develop into squamous cell carcinoma.


Basel Cell Carcinoma
A malignant skin tumour involving cancerous changes of skin cells. Symptoms include a new skin growth that ulcerates, bleeds easily, or does not heal.


Broad-spectrum
Refers to the ability of a sunscreen to protect the skin against both UVA and UVB radiation from the sun.


Cancer
The uncontrolled growth of abnormal cells, which have mutated from normal cells. There are at least 200 different kinds of cancers, which can develop in almost any organ of the body. Cancer can prevent normal function of affected organs, or can spread throughout the body, damaging other important body systems. When this occurs, cancer can lead to death.


Carcinogen
A substance or agent known to cause cancer.


Cataracts
A cloudy or opaque area in the lens of the eye. Excessive exposure to ultraviolet radiation (sunlight) is a cause of cataracts.


Immune System
A system that works to protect the body from harmful substances. Harmful substances include: micro-organisms, viruses, and foreign objects.


Malignant
Cancer that has the ability to spread to other parts of the body, eventually causing disability or death.


Melanin
The natural substance that gives colour (pigment) to hair, skin and to the iris of the eye.


Melanoma
A malignant skin tumour that involves skin cells that produce pigment (melanin). Melanoma may appear on normal skin or arise from a mole or other skin lesion that has changed in appearance.


Ozone Layer
A thin layer of gas in the atmosphere surrounding the earth. Acts as the planet’s sunscreen or filter to prevent most of the sun’s UV radiation from reaching earth’s surface.


Skin Cancer 
A disease in which skin cells become abnormal, growing and increasing in number uncontrollably.

Sunscreen
A cream, lotion, or oil that protects the skin from the ultraviolet rays of the sun.


SPF – Sun Protection Factor
The degree to which a sunscreen protects the skin from ultraviolet radiation. Levels of SPF can range from 2-70. The higher a sunscreen’s SPF rating, the more it will protect the skin, and the longer it can be exposed to the sun before burning.


Squamous Cell Carcinoma
A malignant skin tumour (internal link) involving the middle portion of the skin layer. Symptoms include any change in an existing wart, mole, or other skin lesion, or the development of a new growth that ulcerates or does not heal.


Tumour
A spontaneous growth of tissue that forms into an abnormal mass. It serves no useful function, and can eventually damage organs and systems in the body.


UV Index
A measure of the intensity of the sun’s UVA and UVB rays using a scale that runs from 0 to 11+. The higher the number, the stronger the radiation from the sun, and the greater the risk for skin damage.


UVA Radiation
The weakest type of UV radiation from the sun. These rays are able to penetrate deep into the skin causing premature aging, wrinkles and some skin cancers.


UVB Radiation
The most harmful type of UV radiation. It mainly affects the outer layers of the skin, causing sunburns, premature aging, cataracts, depression of the immune system  and skin cancer.


UVC Radiation
The strongest form of UV radiation. This type of radiation does not reach earth’s surface as it is absorbed by the atmosphere.


Ultraviolet (UV) Radiation
A type of energy emitted by the sun. It is invisible, and is grouped into three ranges by wavelengths: UVA, UVB, and UVC.