1. The fluid consisting of plasma, blood cells, and platelets that is circulated by the heart through a vertebrate vascular system, carrying oxygen and nutrients to and waste materials away from all body tissues.
2. A functionally similar fluid in animals other than vertebrates; such as, the juice or sap of certain plants.
3. A vital or animating force; such as, lifeblood.
4. One of the four humors of ancient and medieval physiology, identified with the blood found in blood vessels, and thought to cause cheerfulness.

Resembling blood; blood-red.

Something that survives by circulating: blood quotes.

Living in, or inhabiting, blood which parasites are known to do.

Monitoring of a patient that allows the blood pressure to be recorded at regular intervals under normal living and working conditions and is useful to determine to what degree a patient's blood pressure falls at night compared to daytime values: Ambulatory blood pressure monitoring consists of prolonged blood pressure readings that are made while a patient does normal daily activities that will allow quantitative analyses of high blood pressure loads over different times and which can help distinguish between types of hypertensions; as well as, to determine the effectiveness of antihypertensive therapies.

Having two stable, genetically distinct lines of blood cells, which can often be distinguished based on differences in blood group antigens.

In humans, this usually rises when blood cells from one dizygous twin mixes with the co-twin in utero; the organ in a woman’s body where babies develop before birth.

The introduction of serum to the blood based on the outmoded belief that it would dilute noxious substances.

Everyone’s blood falls into one of four groups, or types: A, B, AB, or O.

The type of blood depends on the presence, or absence, of certain substances on red the blood cells. Blood types are inherited.

In blood transfusions, the people giving and those receiving the blood must belong to the same blood type (blood group), or a dangerous reaction will take place from the agglutination that occurs when blood of a different group is present.

One exception is that group 0 Rhesus-negative blood can be used in an emergency for anyone.

A transfer of vital bodily fluid that is obtained from a dead body within a short time after a person's death: Cadaver blood transfusion is acceptable for movement into other living humans.

A device for heating blood before infusions; especially, in cases of massive transfusions in which cold blood might cause a state of shock to the body of the patient.

The electric blood warmer includes a container with an electric heater and space for the insertion of a disposable blood-warming bag composed of parallel plastic tubes.

The bodily fluid that exists in various products of the body which is too difficult to see or to find: There are situations in which blood exists in such small quantities; such as, in feces, that the only way to find any occult blood is by microscopic examinations or by chemical procedures.

Sometimes, determining whether a patient has colorectal (colon and rectum) cancer is done by testing the occult blood in the feces of those who are suffering from some ailment but who do not show any obvious symptoms or indications of what is actually causing their discomfort.