An<unk> is a method of putting liquid into the body with a hollow needle and a syringe which is pierced through the skin to a sufficient depth for the material to be forced into the body.  An<unk> follows a parenteral route of administration, that is, its effect is not necessarily local to the area in which the<unk> is administered; it is systemic.
There are several types of<unk>  or infusions, including intradermal, subcutaneous, and intramuscular<unk> , and intravenous or intraosseous infusions.  Long-acting forms of subcutaneous/intramuscular<unk>  are available for various drugs; these are called depot<unk> .
Injection 
Intramuscular injection
Regret 
Transfusion medicine
Inhalation
Dressing 
Recluse
Fluid