| pericranium |
the external periosteum covering the outer surface of the skull. |
| perigee |
in astronomy, the point in the orbit of a moon or other satellite at which it is closest to the earth. (Cf. apogee.) |
| perigynous |
of sepals, petals, and stamens, attached to the edges of a cuplike structure that surrounds the ovary but is not connected to it. (Cf. epigynous, hypogynous.) |
| perihelion |
the point in the orbit of a planet or other body at which it comes closest to the sun. (Cf. aphelion.) |
| peril |
the condition of being in danger; jeopardy; risk. [3 definitions] |
| perilous |
causing or involving great danger; risky; hazardous. |
| perilymph |
the fluid between the bony and membranous labyrinths of the ear. |
| perimeter |
the boundary or border of a closed, two-dimensional figure or area. [2 definitions] |
| perineum |
the area of the body between the thighs, esp. the area between the anus and the vulva in the female and the anus and the scrotum in the male. |
| period |
a specific, limited interval or span of time. [8 definitions] |
| periodic |
recurring or reappearing at regular intervals of time. [3 definitions] |
| periodical |
a publication composed of issues that appear at regular intervals. [3 definitions] |
| periodicity |
the tendency to recur at regular intervals. [2 definitions] |
| 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] |