Pressor: Causing a rise in blood pressure.
A pressor base is a substance (chemically classified as a base) capable of raising the blood pressure.
A pressor nerve is a nerve that, when stimulated, increases the blood pressure.
A pressor reflex is a nerve reflex that constricts arterioles (small blood vessels) and thereby increases the blood pressure.
A pressor substance is any substance that elevates arterial blood pressure. For example, prostacyclin (also known as prostaglandin PGI2) is a potent pressor agent.
The word "pressor" comes from the French verb "presser" meaning "to exert pressure" or "to squeeze."