ExpertGlossary terms starting with P

3,647 terms

Placenta The organ that nourishes the developing fetus in the uterus.
placental blood transplantation (pluh-SEN-tul blud tranz-plan-TAY-shun) The transfer of blood from a placenta to an individual whose own blood production system is suppressed.
Placer An alluvial deposit of sand and gravel containing valuable minerals. (nps geo)
Placer mining That form of mining in which the surficial detritus is washed for gold or other valuable minerals.
Placer mining claim Minerals are loose on the ground or in a streambed.
Plage In solar-terrestrial terms, an extended emission feature of an active region that exists from the emergence of the first magnetic flux until the widely…
Plage Corridor In solar-terrestrial terms, a space in chromospheric plage lacking plage intensity, coinciding with polarity inversion line.
Plagenil In solar-terrestrial terms, spotless disc free of calcium plage.
plain old telephone service (POTS) A call that requires nothing more than basic call handling. [T1.667-1999]
Plain Text The least formatted and therefore most portable form of text for computerized documents.
Plains An extensive area that ranges from level to gently sloping or undulating.
Plaintext The least formatted and therefore most portable form of text for computerized documents.
Plaintext Key An unencrypted cryptographic key.
plaintiff A person or business that files a formal complaint with the court.
Plaintiff/Complainant The party (a person, a partnership, or a corporation) that started the lawsuit by filing and serving the Complaint, Petition, or Affidavit.
Plan A benefit your employer, union or other group sponsor provides to you to pay for your health care services.
Plan administrator A plan administrator is the person or company your employer selects to manage its retirement savings plan.
Plan B A form of the hormone progesterone that is made in the laboratory and used to prevent pregnancy.
Plan of Action and Milestones (POA&M) A document that identifies tasks needing to be accomplished. It details resources required to accomplish the elements of the plan, any milestones in…
plan of reorganization Sets out how a debtor in Chapter 11 reorganization proposes to repay its creditors.
Plan participant If you're enrolled in an employee retirement plan, such as a 401(k) or pension plan, you're a plan participant with certain rights and protections…
Plan Position Indicator An acronym for Plan Position Indicator. A PPI displays radar data horizontally using a map projection.
Plan provider The plan provider of a retirement savings plan, such as a 401(k), 403(b), or 457 plan is the mutual fund company, insurance company, brokerage firm, or…
Plan sponsor The plan sponsor of a retirement savings plan is an employer who offers a retirement savings plan to employees.
Plan Year A 12-month period of benefits coverage under a group health plan. This 12-month period may not be the same as the calendar year.
planar array An antenna in which all of the elements, both active and parasitic, are in one plane.
planar waveguide Synonym slab-dielectric waveguide.
Planck Time The period of time immediately after the creation of the universe (10-43 s) during which quantum gravity is the principal phenomenon governing the…
Planck's constant The constant of proportionality, represented by the symbol h, that relates the energy E of a photon with the frequency of the associated wave through the…
Planck's law The fundamental law of quantum theory that describes the essential concept of the quanta of electromagnetic energy.
plane A part of the intelligent network conceptual model. [T1.667-1999]
plane polarization Synonym linear polarization.
plane wave A wave whose surfaces of constant phase are infinite parallel planes normal to the direction of propagation. 2.
Planetary Boundary Layer The layer within the atmosphere between 1 km and the earth's surface where friction affects wind speed and wind direction.
Planetary boundary layer turbulence structure In the Earth's atmosphere, the planetary boundary layer is the air layer near the ground that is affected by diurnal heat, moisture, or momentum transfer…
Planimeter A device that measures area.
planimetric The horizontal (x,y) locations of non-topographic features, such as rivers, lakes, buildings, roads, etc.
planimetric data Data about features on the Earth surface that are represented only by their correct horizontal position.
Planimetric Map Contains point and line map layers of visible features from aerial photography, such as streets, sidewalks, alleys, buildings, open space, utilities, etc.
Plankton Collectively, all organisms (plants and animals) suspended in the water which are not independent of water movements.
Plankton (planktonic) The aggregate of small plant and animal organisms that float or drift in fresh or salt water.
Plankton bloom A dense growth of microscopic plants and animals (plank-ton) that causes the water to be green, brown, or soupy in appearance.
planktonic foraminifera Marine zooplankton that passively float or weakly swim, and have calcium carbonate skeletons that are present in large numbers on the surface of the ocean.
planned downtime An anticipated period of time when nodes are taken down for hardware maintenance, software maintenance (OS and application), backup, reorganization…
Planned Unit Development (PUD) A real estate project in which individuals hold title to a residential lot and home while the common facilities are owned and maintained by a homeowners'…
Planning The process of setting development goals and policy, gathering and evaluating information, and developing alternatives for future actions based on the…
Planning basis Guidance concerning: (1) size of planning area (distance); (2) time dependence of releases; and (3) flood characteristics of releases.
Planning Council A planning body appointed or established by the Chief Elected Official of an EMA whose basic function is to assess needs, establish a plan for the…
Planning Process Steps taken and methods used to collect information, analyze and interpret it, set priorities, and prepare a plan for rational decision making.
Planning standard(s) Standards which emergency plans of the dam operating organization and local authorities should conform to.
Planning, Land Use, and Zoning For example, resources describing zoning maps, and information used for planning the environment.
Planning, Programming, Budgeting System (PPBS) The primary resource allocation process of DoD . One of three major decisionmaking support systems for defense acquisition.
Plant Station where mechanical, chemical, and/or nuclear energy is converted into electric energy.
plant application (patent) are applications to protect invented or discovered, asexually reproduced plant varieties.
Plant association A grouping of plant species, or a plant community, that recurs across the landscape.
plant breeders' rights (Abbreviation: PBR). Legal protection of a new plant variety granted to the breeder or his successor in title.
plant cell culture In vitro growth of plant cells.
plant cell immobilization Entrapment of plant cells in gel matrices so that they are protected from physical damage.
Plant factor The capacity factor of an entire generating facility including all available generating units. (See also capacity factor)
plant genetic resources (Abbreviation: PGR). The reproductive or vegetative propagating material of: 1.
plant growth regulator An organic compound, either natural or synthetic, and other than a nutrient, that modifies or controls one or more specific physiological processes within…
plant hormone See: plant growth regulator.
plant patent may be granted to anyone who invents or discovers and asexually reproduces any distinct and new variety of plant. --see also patent
Plant Pest Act (PPA) See U.S. Department of Agriculture.
plant sterol A plant-based compound that can compete with dietary cholesterol to be absorbed by the intestines, resulting in lower blood cholesterol levels.
Plant Variety Act (PVA) See U.S. Department of Agriculture.
plant variety protection (Abbreviation: PVP). Synonym for plant breeders' rights.
plant variety rights See: plant breeders' rights.
Plant-incorporated protectants Formerly referred to as plant-pesticides, plant-incorporated protectants (PIPs) are substances that act like pesticides produced and used by a plant to…
Plant-use electricity The electric energy used in the operation of a plant. This energy total is subtracted from the gross energy production of the plant; for reporting…
plantibody An antibody expressed transgenically in an engineered plant.
plantlet A small rooted shoot regenerated from cell culture following embryogenesis or organogenesis.
plaque A film of mucus that traps bacteria on the surface of the teeth. Plaque can be removed with daily brushing and flossing of teeth.
plaque (plak) In medicine, a small, abnormal patch of tissue on a body part or an organ. Plaques may also be a build-up of substances from a fluid, such as cholesterol…
plaque radiotherapy (PLAK RAY-dee-oh-THAYR-uh-pee) A type of radiation therapy used to treat eye tumors.
Plasma (PLAZ-muh) The clear, yellowish, fluid part of the blood that carries the blood cells. The proteins that form blood clots are in plasma.
plasma cell (PLAZ-muh SEL) A type of white blood cell that produces antibodies.
plasma cell myeloma (PLAZ-muh SEL MY-eh-LOH-muh) A type of cancer that begins in plasma cells (white blood cells that produce antibodies).
plasma cell tumor (PLAZ-muh SEL TOO-mer) A tumor that begins in plasma cells (white blood cells that produce antibodies).
plasma cells Antibody-producing white blood cells derived from B lymphocyte s.
plasma membrane (PLAZ-muh MEM-brayn) The outer membrane of a cell.
plasmacytic (PLAZ-muh-SIH-tik) Having to do with plasma cells (a type of white blood cells).
plasmacytoma (PLAZ-muh-sy-TOH-muh) A type of cancer that begins in plasma cells (white blood cells that produce antibodies).
plasmalemma The lipid bilayer and associated proteins and other molecules that surrounding the protoplast, within the cell wall.
plasmapheresis (PLAZ-muh-feh-REE-sis) The process of separating certain cells from the plasma in the blood by a machine; only the cells are returned to the person.
Plasmid An circular self-replicating non-chromosomal DNA molecule found in many bacteria, capable of transfer between bacterial cells of the same species, and…
Plasmid (p) A circular DNA molecule, capable of autonomous replication, which typically carries one or more genes encoding antibiotic resistance proteins.
plasmodesma (pl.: plasmodesmata) Fine protoplasmic thread that connects adjacent plant cells by passing through the plant cell wall.
Plasmodium The genus of the parasite that causes malaria. The genus includes many species.
plasmolysis Shrinkage of protoplasm caused by removal of water from a cell through osmosis when surrounded by a hypertonic solution.
Plastic limit The water content corresponding to an arbitrary limit between the plastic and the semisolid state of consistency of a soil; water content at which a soil…
Plastic soil A soil that exhibits plasticity.
Plastic Surgeon A surgeon who specializes in reducing scarring or disfigurement that may occur as a result of accidents, birth defects, or treatment for diseases.
plastic surgery An operation that restores or improves the appearance of body structures.
plastic-clad silica (PCS) fiber An optical fiber that has a silica-based core and a plastic cladding. Note 1: The cladding of a PCS fiber should not be confused with the polymer overcoat…
Plasticity A phenomenon used to describe a cell that is capable of becoming a specialized cell type of different tissue.
Plasticity index Numerical difference between the liquid limit and the plastic limit.
plastid A general term for a number of plant s which carry non-nuclear DNA. Includes the pigment -carrying bodies: 1. chloroplasts in leaves, 2.
plastoquinone One of a group of compounds involved in the transport of electrons as part of the process of photosynthesis.
plate 1. Verb: to distribute a thin film of micro-organisms or plant cells onto a solid medium. 2. Noun: refers to the two segments of a Petri dish or similar.