The largest organ in the system is the skin. It protects and supports our body. We must take care of it. Many people will rub lotion on it because the skin can dry out and needs moisture. Other people will rub sunscreen on it so that the sun will not damage their skin. When someone applies something like lotion or sunscreen to their skin, this term is referred to as subcutaneous.
Subcutaneous mostly means that it is also applied to underneath the skin. An example of this is the subcutaneous injection. This means that a shot or needle is place just underneath the skin. If a person is dehydrated, then a subcutaneous injection may be needed because this person needs moisture under the skin.