Anabolism

Chemical reactions that take place in the body that create larger molecules out of smaller ones. These reactions are key for creating more complex living matter, mainly muscle.

Anabolic

A word which refers to anabolism and means, more or less, has constructive properties.

Anabolic steroid

Any one of several chemical compounds derived from testosterone or prepared artificially to promote general body growth which promote masculinization effects.

Androgen

Any steroid hormone that promotes male characteristics.

ATP

Adenosine triphosphate is a molecule used to store and release energy in the muscle.

Atrophy

A state of deterioration usually within the muscle or bodily organ due to a lack of use or health.

Cholesterol

A fatty substance found in animal products that performs many vital functions. It is synthesized by the liver and the adrenal cortex.

Creatine (Not a steroid)

A compound that is produced naturally in the body, and produces ATP, a molecule that stores, and releases energy in muscles, when it is combined with phosphate.

Cycle

An amount of time in which a certain supplement is taken. Usually the time on a cycle is followed by the same amount of time off of the cycle.

Dart, pin, poke, ned, stick

Slang terms for syringes.

Diuretic

A substance that increases the amount of urine which is released by the kidneys.

Estrogen

A natural hormone that promotes the growth and development of female characteristics.

Fakes or basement drug

A term for counterfeit or fake steroids.

Gear

Slang for steroids, syringes, anything associated with the use of steroids.

Gynecomastia

An abnormal enlargement of one or both breasts in men. This condition is usually temporary due to a hormonal imbalance brought on by the use of steroids, however, can occur naturally as well.

Immune system

The system in a person’s body that wards off infection and responds to illness.

Juice, Sauce, Slop

Slang terms for injectable steroids.

Lean mass

The amount of muscle on a person’s body.

Roid rage

A term given to people who act in very aggressive or hostile manner after taking large doses, usually on a regular basis, of anabolic steroids, sometimes nicknamed roids.

Steroid

A general term for hormonal substances with the same basic chemical structure produced mainly in the adrenal cortex and gonads.

Testosterone

An male hormone which is used to produce anabolic steroids.

Thermogenisis

The production of heat. Heat raises metabolism so it is easier to burn fat.

Sources:
Steroidology [1]
Wise Geek [2]