1. A fluid substance; a body whose particles move easily among themselves.
Fluid is a generic term, including liquids and gases as species. Water, air, and steam are fluids. By analogy, the term is sometimes applied to electricity and magnetism, as in phrases electric fluid, magnetic fluid, though not strictly appropriate.
or Fluid drachm
a measure of capacity equal to one eighth of a fluid ounce.
(a) In the United States, a measure of capacity, in apothecaries' or wine measure, equal to one sixteenth of a pint or 29.57 cubic centimeters. This, for water, is about 1.04158 ounces avoirdupois, or 455.6 grains. (b) In England, a measure of capacity equal to the twentieth part of an imperial pint. For water, this is the weight of the avoirdupois ounce, or 437.5 grains.
Fluids of the body
(Physiol.) The circulating blood and lymph, the chyle, the gastric, pancreatic, and intestinal juices, the saliva, bile, urine, aqueous humor, and muscle serum are the more important fluids of the body. The tissues themselves contain a large amount of combined water, so much, that an entire human body dried in vacuo with a very moderate degree of heat gives about 66 per cent of water.
etc. See under Burning, Elastic, etc.