proto-, prot- +

(Greek: first; foremost, front, earliest form of, original, primitive; chief, principal; usually used as a prefix)

protopathic sensibility
A reference to the bodily sensations of fast localized pain, slow, poorly localized pain, and temperature.

Protopathic sensibility is transmitted principally along the thinnest nerve fibers, which lack a myelin sheath and conduct nerve impulses slowly.

It is related primarily to the spinothalamic system (extending between the spinal cord and the thalamus which is the large oval area of gray matter within the brain that relays nerve impulses from the basal ganglia to the cerebellum, both parts of the brain that control and regulate muscle movement), whose receptive neuron fields are often nonspecific and very large, covering the entire body.

A division of the plant kingdom, according to one system of classification, set up to include the bacteria, the blue-green algae, and the viruses.
Any unicellular plant, or plant forming only a plasmodium (mass of protoplasm), having reproduction only by fission (cell division), gemmation (process of budding), or cell division.

The protophytes (Protophyta) are by some botanists considered an independent branch or class of the vegetable kingdom, and made to include the lowest forms of both fungi and algae; such as, slime molds, Bacteria, the nostocs, etc.

protoplanetary disk
A rotating disk of dust and gas which surrounds the core of a developing solar system.

It may eventually develop into orbiting celestial bodies; such as, planets and asteroids.

1. The complex, semifluid, translucent substance that constitutes the living matter of plant and animal cells and clearly presents the essential life functions of a cell.

Composed of proteins, fats, and other molecules suspended in water, it includes the nucleus and cytoplasm.

2. The colorless liquid or jelly contents of a living cell, composed of proteins, fats, and other organic substances in water and which is regarded as the physical basis of all living matter and life functions.

At first, Czech physiologist Jan Evangelista Purkinje gave the name protoplasm to the living material within the cell, in 1839.

He referred specifically to the gelatinous embryonic material in an egg because this first-formed material reminded him of the word protoplasm which was used to describe Adam, the first formed man, in the Bible.

—Compiled from information provided in
Encyclopedia of Word and Phrase Origins;
by Robert Hendrickson; Facts On File, Inc.; New York; 1997; page 547.
1. Pertaining to or referring to the first formation of living bodies.
2. A reference to protoplasm, the substance of which animal and vegetable cells are formed.
3. Consisting of, or resembling, protoplasm which is the entire contents of a live cell.
1. That which is formed first.
2. The living portion of a cell considered as a unit which includes the cytoplasm, the nucleus, and the plasma membrane.

3. A plant, fungal, or bacterial cell that has had its cell wall removed.
4. The living substance of a plant or bacterial cell, excluding the cell wall.
The primary prepenna (a nestling down feather which is succeeded by an adult contour feather), succeeded by mesoptile.
Classified as being the same as Chasmosaurus, “cleft lizard” from Alberta and New Mexico.
An instrument for recording the beginning or first trace of an earthquake shock.
The process and instrument for recording the beginning or first trace of an earthquake shock.
1. A contracting gas cloud in the embryonic of beginning stage of a star formation before the onset or beginning of thermonuclear reactions in its interior.
2. A celestial object made of a contracting cloud of interstellar medium (mostly hydrogen gas) which eventually becomes a main-sequence star.

Less massive protostars may take hundres of millions of years to evolve into stars; massive ones contract more quickly and may take only a few hundred thousand years to evolve.

protostele, protostelic
1. The dense central cylinder of roots and young stems.
2. A simple type of stele in which a central core of xylem is surrounded by a cylinder of phloem (inner fibrous bark of certain trees).
Any of a major group of animals defined by its embryonic development, in which the first opening in the embryo becomes the mouth.

At this stage of development, the later specialization of any given embryonic cell has already been determined.

Protostomes are on of the two groups of animals having a true body cavity (coelom) and are believed to share a common ancestor. They include the mollusks (nails, slugs, clams, mussels, cuttlefish, and octopuses), annelids (segmented worms, earthworms, lugworms, and leeches), and arthropods (insects; including mosquitoes, ticks, centipedes, spiders and many other species).

Referring to, or relating to, the earliest period in time or development.

It has been applied to the early period of infancy, when the child has no awareness of himself or herself as being distinct from others and no real concept of time or space.