| periodic law |
the principle that the properties of the chemical elements recur periodically when the elements are arranged in increasing order of their atomic numbers. |
| periodic system |
a system of classifying the chemical elements, based on the periodic law. |
| periodic table |
a table that illustrates the periodic system of the chemical elements, classified according to atomic number. |
| periodization |
the dividing of history into chronological periods. |
| periodontal |
of or relating to the tissue, bones, and gums that surround and support the teeth. |
| periodontics |
(used with a sing. verb) the branch of dentistry concerned with diseases and treatment of the gums, bones, and tissues surrounding the teeth. |
| periosteum |
a tough, fibrous membrane that covers all bones except at the joints. |
| peripatetic |
walking or traveling around; going from place to place; itinerant. [2 definitions] |
| peripheral |
of, relating to, or forming a periphery. [3 definitions] |
| peripheral vision |
the ability to see objects and motion to either side while looking straight ahead. |
| periphery |
the outer boundary or edge of an area or surface, or the region directly inside or outside of this. [2 definitions] |
| periphrasis |
an indirect or roundabout way of phrasing something; circumlocution. [2 definitions] |
| periphrastic |
roundabout; circumlocutory. [2 definitions] |
| perique |
a strong, rich, black tobacco grown in Louisiana that is used mainly in blends. |
| perisarc |
the tough nonliving outer layer that encloses many hydrozoans. |
| periscope |
a tubular optical instrument fitted with mirrors and prisms so as to allow one to see what is not in the direct line of sight or what is obstructed from sight. |
| perish |
to die or be destroyed, esp. in an untimely or unnatural way. [2 definitions] |
| perishable |
subject to death, decay, or destruction. [3 definitions] |
| peristalsis |
a process of muscular contractions and relaxations along a tubular muscular system, such as that which forces food through the digestive system. |
| peristome |
the area or appendages surrounding certain mouthlike openings, as in mosses and some invertebrates. |
| peristyle |
a row or series of architectural columns forming an enclosure around a building or open space, or the open space so enclosed, esp. as used in classical Greek architecture or copies of it. |